JP7028124B2 - CPU unit, CPU unit control method, information processing program, and recording medium - Google Patents

Description

The present invention relates to a CPU unit or the like that is duplicated in a controller.

Conventionally, with respect to PLC (Programmable Logic Controller), a configuration in which a CPU unit is duplicated is known for the purpose of improving the safety and reliability of the system. For example, in Patent Document 1 below, the CPU unit of the executing system acquires the unit version of the CPU unit of the standby system prior to the start of the redundant operation, and the unit version is compared with the functional version that is stored and retained by itself. Discloses a configuration that determines that duplicate operation is possible when is a functional version or higher. Hereinafter, the conventional duplication of the CPU unit in the PLC will be described with reference to FIGS. 8 and 9.

FIG. 8 is a diagram illustrating an outline of conventional processing of the CPU unit duplicated in the PLC. As illustrated in FIG. 8, each of the CPU units duplicated in the PLC repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. The period from the execution of the I / O refresh process to the execution of the next I / O refresh process is also referred to as "1 cycle (1 cycle)". That is, each of the CPU units duplicated in the PLC executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order in "1 cycle (1 cycle)". The period required for "one cycle" (that is, the period from the execution of the I / O refresh process to the execution of the next I / O refresh) is also referred to as "cycle time".

The self-diagnosis process is a process of diagnosing whether the hardware of the own unit is operating normally, and in particular, whether there is an abnormality in the memory, the hard disk, or the like. The instruction execution process is a process for executing a user program or the like, and various operations are executed using the data acquired in the I / O refresh process executed in the previous cycle, and the I / O refresh process in the current cycle is executed. It is a process to generate the data to be output in. The I / O refresh process is a process for executing data exchange with an external device and an external unit other than the duplicated CPU unit of the other party, outputs the data generated in the immediately preceding instruction execution process, and has the next cycle. This is the process of acquiring the data used for the instruction execution process of.

One of the CPU units to be duplicated in the PLC is the execution system and the other is the standby system (STB), and the state of the duplicated CPU unit of the other party is confirmed with each other. Then, when the CPU unit of the execution system goes down, the CPU unit of the standby system switches to the down CPU unit of the execution system and continues the operation. Hereinafter, the CPU unit as an active system may be abbreviated as "ACT", and the CPU unit as a standby system may be abbreviated as "STB".

As shown in FIG. 8, the ACT and the STB are synchronized in the middle of the internal processing of each CPU unit in order to smoothly switch from the ACT to the STB when the ACT goes down. That is, in each of the ACT and STB, an abnormality occurs in the other unit to be duplicated at the timing when the own unit completes the execution of each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. Make sure you haven't. "Confirmation processing that no abnormality has occurred in the other party's unit to be duplicated" that is executed when the own unit completes the execution of each of the self-diagnosis processing, instruction execution processing, and I / O refresh processing. Is also referred to as "synchronous check processing".

By synchronizing in the middle of the internal processing, the cycle of each CPU unit (more accurately, the start time of the internal processing of each CPU unit) does not deviate, and the CPU units to be duplicated perform the same processing at the same timing. Can be done with. Each of the ACT and STB executes a synchronization check process at the completion of each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process, and synchronization (that is, an abnormality occurs in the other unit). After confirming that it has not been executed, the execution of the next process is started. Therefore, each of the ACT and the STB can start each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process at the same timing.

Each of the ACT and STB basically monitors the state of the other party (in other words, confirms) in this synchronization check process, and if the ACT is abnormally stopped, the STB replaces the abnormally stopped ACT. And take over the driving.

Here, assuming the case where "ACT or STB cannot detect an abnormality of the synchronization target (that is, the duplicated CPU unit of the other party) (in particular, ACT cannot detect an abnormality of STB)", the ACT and STB Each executes the synchronization check process as follows. That is, if each of the ACT and STB cannot acquire the response of the other CPU unit within a predetermined period in each synchronization check process, "an error has occurred in the duplicated CPU unit of the other party (that is, a synchronization error). Has occurred) ”. Specifically, each of the ACT and STB is "duplicated" when the notification that "the execution of the corresponding process is completed" cannot be obtained from the CPU unit of the other party in each synchronization check process within the determination period. An error has occurred in the CPU unit of the other party. "

When it is determined that "an abnormality has occurred in the CPU unit of the other party to be duplicated", each of the ACT and STB executes the process of "removing the duplication". By "removing the duplication", each of the ACT and the STB prevents "the cycle time becomes extremely long by maintaining the synchronization with the CPU unit of the other party in which the abnormality has occurred". If the duplication is not canceled, that is, "the execution of the next process is not started until it can be confirmed that the other party's unit has not occurred", and if the other party's CPU unit has an error, "the other party's unit" It cannot be confirmed that there is no abnormality in the CPU. Therefore, the execution of the next process cannot be started, and the cycle time becomes extremely long.

FIG. 9 is a diagram illustrating details of a synchronization check process executed at the time when each of the self-diagnosis process, the instruction execution process, and the I / O refresh process is completed. As described above, in the synchronization check process, each of the ACT and the STB confirms whether or not the notification to the effect that "the execution of the corresponding process has been completed" can be obtained from the CPU unit of the other party within the determination period.

The synchronization check process is performed, for example, by providing a register (common register) that each CPU unit can read and write to each other inside or outside each of the CPU units (that is, ACT and STB) to be duplicated in the PLC. ,realizable. Each CPU unit "executes the process by its own unit" at the time when the processes up to the synchronization check process are completed, that is, at the time when each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process is completed. Is completed. ”Written to the common register. Each CPU unit reads that "the own unit has completed the execution of the process" written in the common register by the CPU unit of the other party, thereby indicating that the CPU unit of the other party has completed the execution of the process. confirm.

That is, as illustrated in FIG. 9, when the CPU unit 99P completes the processing, that is, when the execution of the processing is completed, the processing is completed in REG1 of the common register 98 (that is, "the own unit processes". The execution of "Completed") is written. The CPU unit 99Q recognizes that the processing is completed by the CPU unit 99P by reading the REG1. Further, when the CPU unit 99Q completes the processing, that is, when the processing execution is completed, the processing is completed in REG2 of the common register 98 (that is, "the own unit has completed the processing execution"). To write. By reading REG2, the CPU unit 99P recognizes that the processing has been completed by the CPU unit 99Q. When the CPU unit 99P and the CPU unit 99Q recognize each other that the processing is completed, the CPU unit 99P and the CPU unit 99Q move to the next processing, respectively.

When the synchronization check process using the common register 98 is adopted and an error occurs in the CPU unit of the other party, the fact that "the own unit has completed the execution of the process" by the CPU unit of the other party is written in the common register 98. do not have. Therefore, each CPU unit waits for a predetermined period from the time when the execution of the processing by the own unit is completed, and then writes to the common register 98 to the effect that "the own unit has completed the execution of the processing" by the CPU unit of the other party. Determine the presence or absence. For example, the CPU unit 99P does not write to REG2 that "the own unit has completed the execution of the process" even after a predetermined period has elapsed from the time when the CPU unit 99P completes the execution of the process. It is determined that an abnormality has occurred in 99Q. Even if a predetermined period has elapsed from the time when the CPU unit 99Q completes the execution of the process, the CPU unit 99Q does not write to the CPU unit 99P that "the own unit has completed the execution of the process" to the REG1. Judge that an abnormality has occurred. In the following description, each CPU unit determines whether or not the other CPU unit has written "the own unit has completed the execution of the process" from the time when the execution of the process by the own unit is completed. The predetermined period is also referred to as "waiting time".

Japanese Unexamined Patent Publication No. 2005-122716

The conventional technology as described above is based on the premise that the hardware of the CPU unit to be duplicated in the PLC is almost the same, that is, both have almost the same processing power, and both have the processing power. There is a problem that it is not possible to assume different cases.

Conventionally, on the premise that the processing capacity of the duplicated CPU units is almost the same, each CPU unit has a common "waiting time" among the duplicated CPU units from the time when the execution of the processing by the own unit is completed. After that, the abnormality of the CPU unit of the other party is determined.

The reason why the conventional CPU units to be duplicated perform the synchronization check process using the common "waiting time" is as follows. That is, under the premise that the processing capabilities of the duplicated CPU units are the same, the time points at which the execution of the processing by the duplicated CPU units is completed should be approximately the same timing. In other words, under the premise that the processing capacity of the own unit and the CPU unit of the other party to be duplicated are the same, the time when the execution of the processing by the own unit is completed and the execution of the processing by the CPU unit of the other party are completed. It should be about the same timing as the time point. Therefore, in each of the CPU units to be duplicated, the "waiting time" used to determine the abnormality of the CPU unit of the other party, that is, used for the synchronization check process, is conventionally common to the CPU units to be duplicated. It was a fixed period of length.

However, the CPU unit is often used for a long period of time, for example, about 20 years or more, and during that time, the parts used in the CPU unit are discontinued, and the CPU unit is significantly renewed. May be done. Then, for example, when the hardware of the CPU unit is significantly renewed, it is conceivable that the performance of the CPU unit, that is, the processing capacity, changes significantly before and after the renewal.

When the CPU unit before the renewal and the CPU unit after the renewal are duplicated, if the "waiting time" used for the synchronization check process is common to the duplicated CPU units, the synchronization check process cannot be executed correctly, etc. Problem occurs.

(Occurrence of erroneous judgment)
That is, even if the processing is the same, the CPU unit before the renewal and the CPU unit after the renewal have different execution completion points. Therefore, if the determination is executed after the common "waiting time", the CPU unit of the other party normally operates. Even if it is operating, it will be erroneously determined as abnormal.

For example, if the processing capacity is increased four times as much as before the renewal due to the renewal, and the CPU unit after the renewal is about "10 ms (milliseconds)" for the period required to execute a certain process, the CPU before the renewal is performed. The unit will be about "40ms". Then, if the "waiting time" used for the synchronization check process between the CPU unit before the renewal and the CPU unit after the renewal is fixed to "5 ms" which is common to both units, the CPU unit after the renewal is as follows. It makes a judgment.

That is, the CPU unit after the renewal synchronizes when "5 ms" has elapsed from the time when the own unit completes the execution of the certain process, that is, the CPU unit before the renewal executes the certain process. Determine if it is complete. However, the CPU unit before the renewal can complete the execution of the certain process only after "30 ms" has elapsed from "the time when the CPU unit after the renewal completes the execution of the certain process". Therefore, when 5 ms has elapsed from the time when the own unit completes the execution of the certain process, the CPU unit after the renewal has "the CPU unit before the renewal executes the certain process" from the CPU unit before the renewal. I can't get a notification that "completed". Therefore, the CPU unit after the renewal mistakenly states that "an error has occurred in the CPU unit before the renewal (that is, a synchronization error has occurred)" even if the CPU unit before the renewal is operating normally. Will be judged.

(Occurrence of judgment delay)
In the above example, by fixing the "waiting time" common to the CPU unit before the renewal and the CPU unit after the renewal to, for example, "30 ms", it is possible to prevent erroneous determination by the CPU unit after the renewal. ..

That is, the CPU unit before the renewal can complete the execution of the certain process if "30 ms" has elapsed from "the time when the CPU unit after the renewal completes the execution of the certain process". .. Therefore, the CPU unit after the renewal asks "whether or not an abnormality has occurred in the CPU unit before the renewal" if "30 ms" has elapsed from the time when the own unit completes the execution of the certain process. It can be judged correctly.

However, since the waiting time of "30 ms" is common to the CPU unit before the renewal and the CPU unit after the renewal, the CPU unit before the renewal starts from the time when the own unit completes the execution of the certain process. The determination is made after "30 ms" has elapsed. That is, the CPU unit before the renewal determines "whether or not an abnormality has occurred in the CPU unit after the renewal" after "30 ms" has elapsed from the time when the own unit completes the execution of the certain process.

Since the CPU unit before the renewal and the CPU unit after the renewal recognize each other's processing completion of the CPU unit of the other party and then move to the next processing, the waiting time of both is set to "30 ms" common to both. Then, the start of execution of the next process is delayed. The CPU unit after the renewal determines the abnormality of the CPU unit of the other party after "30 ms" has elapsed from the time when the own unit completes the execution of the certain process, and further, after the "30 ms", the CPU unit before the renewal. Abnormality judgment is executed by. That is, the CPU unit after the renewal can start the execution of the next process only after "60 ms" from the time when the own unit completes the execution of the certain process. That is, if the waiting time used by the CPU unit before the renewal and the CPU unit after the renewal is set to "30 ms" common to both in accordance with the CPU unit before the renewal, the determination of both is delayed.

The CPU unit before the renewal does not execute the determination until "30 ms" has elapsed from the time when the own unit completes the execution of the certain process. Therefore, if an abnormality occurs in the CPU unit after the renewal, the operation is continued. Switching from ACT to STB for is delayed.

As described above, in the conventional technique on the premise that the CPU units to be duplicated in the PLC have almost the same processing capacity, when the processing capacities of the CPU units to be duplicated are different from each other, erroneous determination and ACT to STB are performed. There is a problem that there is a delay in switching.

In order to solve the above problems, the CPU unit according to one aspect of the present invention is a CPU unit that is duplicated in the controller, and has the processing capacity of the own unit and the processing capacity of the other CPU unit that is duplicated. In consideration of the ratio, the setting unit for setting the waiting time and the processing in the CPU unit of the other party from the time when the execution of the processing in the own unit is completed until the waiting time set by the setting unit elapses. If the execution completion cannot be confirmed, a determination unit for determining that an abnormality has occurred in the CPU unit of the other party is provided.

According to the above configuration, the CPU unit uses the waiting time set in consideration of the ratio of the processing capacity of the own unit and the CPU unit of the other party to the CPU unit of the own unit and the CPU unit of the other party. Judge synchronization (that is, match of processed processes that have been executed).

For example, when the CPU unit of the other party has higher performance (that is, the execution speed of processing is faster) than the own unit, the CPU unit sets a predetermined "normal waiting time" as the waiting time. do. Further, when the performance Ab is equal between the CPU unit of the other party and the own unit, the control method sets a predetermined "normal waiting time" as the waiting time Tw.

If the CPU unit of the other party has higher performance than the own unit, the CPU unit of the other party should have already completed the execution of the certain process when the own unit completes the execution of a certain process. .. Further, when the performance Ab is equal between the CPU unit of the other party and the own unit, the CPU unit of the other party should complete the execution of the certain process when the own unit completes the execution of a certain process.

Therefore, even if the CPU unit of the other party has higher performance than the own unit, the CPU unit may have an abnormality in the CPU unit of the other party by setting the "normal waiting time" as the waiting time. It is possible to accurately determine whether or not it has occurred.

For example, when the CPU unit of the other party has lower performance (that is, the execution speed of processing is slower) than the own unit, the CPU unit considers the performance difference in the normal waiting time as the waiting time. Set the period including the adjustment waiting time. Specifically, the "difference between the time when the execution of the process in the own unit is completed and the time when the execution of the process is expected to be completed in the CPU unit of the other party" is defined as the adjustment waiting time.

When the performance of the CPU unit of the other party is lower than that of the own unit, the CPU unit of the other party has not yet completed the execution of the certain process when the own unit completes the execution of a certain process. Therefore, the CPU unit waits until "a time when the execution of the process is expected to be completed in the other party's CPU unit", and then waits until the "normal waiting time" elapses. Judge whether the execution completion of the process can be confirmed. That is, the CPU unit performs the processing in the other CPU unit from the time when the execution of the processing in the own unit is completed until the "period in which the adjustment waiting time is added to the normal waiting time" elapses. Determine if execution completion can be confirmed.

Therefore, even if the CPU unit of the other party has lower performance than the own unit, the CPU unit sets "a period in which the adjustment waiting time is added to the normal waiting time" as the waiting time. Therefore, the above determination can be accurately executed.

As described above, the CPU unit takes into consideration the difference in the processing capacity between the own unit and the CPU unit of the other party even when the processing capacity of the own unit and the CPU unit of the other party do not match. It has the effect of being able to set an appropriate waiting time. That is, the effect is that the CPU unit can accurately perform the synchronization check process without providing an unnecessary waiting time in consideration of the difference in processing capacity between the CPU unit of the other party to be duplicated and the own unit. Play.

In the CPU unit according to one aspect of the present invention, the processing includes self-diagnosis processing for diagnosing whether or not there is an abnormality in the hardware of the own unit, and instruction execution for generating a signal for controlling an external device other than the other CPU unit. The setting unit includes the self-diagnosis process, the instruction execution process, and the I / O, including the process and the I / O refresh process for exchanging data with an external device other than the CPU unit of the other party. The waiting time may be set for each of the refresh processes, and the determination unit may execute the determination for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process.

According to the above configuration, the CPU unit synchronizes its own unit with the other CPU unit (that is, execution is completed) for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. Matching of the processed processes) is judged.

Therefore, the CPU unit may determine the synchronization between the own unit and the other CPU unit at the timing of completion of each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. It has the effect of being able to do it.

The CPU unit according to one aspect of the present invention has the processing capacity of the other CPU unit before repeatedly executing the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. The duplication process acquired from the CPU unit of the other party may be executed once.

According to the above configuration, the CPU unit repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order with respect to the processing capacity of the other CPU unit. Get it once. Then, the CPU unit sets the waiting time used for the determination for each of the processes in consideration of the ratio between the acquired processing capacity of the other party's CPU unit and the processing capacity of the own unit.

Therefore, the CPU unit sets the waiting time used for the determination for each process in consideration of the processing capacity of the other party's CPU unit acquired in advance before repeatedly executing each process. It has the effect of being able to.

In the CPU unit according to one aspect of the present invention, the setting unit sets the waiting time for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process to the self-diagnosis process and the instruction execution. It may be set in consideration of the ratio of the processing capacity of the own unit and the processing capacity of the CPU unit of the other party related to the execution of each of the processing and the I / O refresh processing.

According to the above configuration, the CPU unit has a processing capacity between the own unit and the other CPU unit related to each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process. The waiting time for each process is set in consideration of the difference.

Therefore, the CPU unit has the processing capabilities of the own unit and the CPU unit of the other party for each of the waiting times of the self-diagnosis process, the instruction execution process, and the I / O refresh process. It has the effect of being able to be set according to.

In order to solve the above problems, the control method according to one aspect of the present invention is the control method of the CPU unit to be duplicated in the controller, and the processing capacity of the own unit and the processing of the CPU unit of the other party to be duplicated. The CPU unit of the other party from the setting step of setting the waiting time in consideration of the ratio with the capacity and the time when the execution of the process in the own unit is completed until the waiting time set in the setting step elapses. It includes a determination step of determining that an abnormality has occurred in the CPU unit of the other party when the completion of execution of the process cannot be confirmed.

According to the above method, in the control method, the own unit and the CPU unit of the other party use the waiting time set in consideration of the ratio of the processing capacity of the own unit and the CPU unit of the other party. Judge synchronization (that is, match of processed processes that have been executed).

For example, when the CPU unit of the other party has higher performance (that is, the execution speed of processing is faster) than the own unit, the control method sets a predetermined "normal waiting time" as the waiting time. do. Further, when the performance Ab is equal between the CPU unit of the other party and the own unit, the control method sets a predetermined "normal waiting time" as the waiting time Tw.

If the CPU unit of the other party has higher performance than the own unit, the CPU unit of the other party should have already completed the execution of the certain process when the own unit completes the execution of a certain process. .. Further, when the performance Ab is equal between the CPU unit of the other party and the own unit, the CPU unit of the other party should complete the execution of the certain process when the own unit completes the execution of a certain process.

Therefore, even if the CPU unit of the other party has higher performance than the own unit, the control method sets the "normal waiting time" as the waiting time, so that the CPU unit of the other party has an abnormality. It is possible to accurately determine whether or not it has occurred.

For example, when the CPU unit of the other party has lower performance (that is, the execution speed of processing is slower) than the own unit, the control method considers the performance difference in the normal waiting time as the waiting time. Set the period including the adjustment waiting time. Specifically, the "difference between the time when the execution of the process in the own unit is completed and the time when the execution of the process is expected to be completed in the CPU unit of the other party" is defined as the adjustment waiting time.

When the performance of the CPU unit of the other party is lower than that of the own unit, the CPU unit of the other party has not yet completed the execution of the certain process when the own unit completes the execution of a certain process. Therefore, the control method waits until "a time when the execution of the process is expected to be completed in the CPU unit of the other party", and then waits until the "normal waiting time" elapses. Judge whether the execution completion of the process can be confirmed. That is, in the control method, the processing in the CPU unit of the other party is performed from the time when the execution of the processing in the own unit is completed until the "period in which the adjustment waiting time is added to the normal waiting time" elapses. Determine if execution completion can be confirmed.

Therefore, even if the CPU unit of the other party has lower performance than the own unit, the control method sets "a period in which the adjustment waiting time is added to the normal waiting time" as the waiting time. Therefore, the above determination can be accurately executed.

As described above, the control method takes into consideration the difference in the processing capacity between the own unit and the CPU unit of the other party even when the processing capacity does not match between the own unit and the CPU unit of the other party. It has the effect of being able to set an appropriate waiting time. That is, the above-mentioned control method has an effect that the synchronization check process can be accurately performed without providing an unnecessary waiting time in consideration of the difference in the processing capacity between the CPU unit of the other party to be duplicated and the own unit. Play.

According to one aspect of the present invention, with respect to the CPU unit to be duplicated in the PLC, a synchronization check is performed without providing an unnecessary waiting time in consideration of the difference in processing capacity between the CPU unit of the other party to be duplicated and the own unit. It has the effect of being able to perform processing accurately.

It is a block diagram which shows the structure of the main part of the CPU unit and the like which concerns on Embodiment 1 of this invention. It is a figure explaining the outline of the process executed by each of the two CPU units shown in FIG. 1. It is a figure explaining the specific example of the process which each of the two CPU units shown in FIG. 1 acquires the performance information which shows the performance of the CPU unit of the other party to be duplicated. It is a block diagram which shows the structure of the main part of the CPU unit and the like which concerns on Embodiment 2 of this invention. It is a figure which shows an example of the hardware configuration which realizes the CPU unit shown in FIG. It is a figure explaining the outline of the process executed by each of the two CPU units shown in FIG. 4. It is a figure explaining the specific example of the process which each of the two CPU units shown in FIG. 4 acquires the performance information which shows the performance of the CPU unit of the other party to be duplicated. It is a figure explaining the outline of the processing of the CPU unit duplicated in a PLC up to the present. It is a figure explaining the details of the synchronization check process which is executed at the time of each execution completion of the self-diagnosis process, the instruction execution process, and the I / O refresh process.

[Embodiment 1]
Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated. In each of the following embodiments, a PLC (Programmable Logic Controller) 10 that controls a control target such as a machine and equipment will be described as a typical example of a controller in which two CPU units are duplicated.

In the following, first, in order to facilitate understanding of each of the first CPU unit 100A and the second CPU unit 100B to be duplicated in the PLC 10, an outline of the processing executed by both of them will be described with reference to FIG.

§1. Application Example FIG. 2 is a diagram illustrating an outline of processing executed by each of two CPU units (that is, the first CPU unit 100A and the second CPU unit 100B) described later with reference to FIG. 1. The first CPU unit 100A and the second CPU unit 100B are duplicated in PLC10, one of which becomes an execution system (ACT) and the other of which becomes a standby system (STB), and each other confirms the state of the other CPU unit. When the CPU unit (ACT) of the executing system goes down, the CPU unit (STB) of the standby system switches to the ACT and continues the operation of the first CPU unit 100A and the second CPU unit 100B. Hereinafter, in order to facilitate understanding, an example in which the first CPU unit 100A is an ACT and the second CPU unit 100B is an STB will be described.

(Summary of waiting time)
As shown in FIG. 2, each of the ACT and the STB repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. Hereinafter, a set of "self-diagnosis processing, instruction execution processing, and I / O refresh processing" that is repeatedly executed in this order is referred to as "1 cycle (1 cycle)".

The self-diagnosis process is a process of diagnosing whether the hardware of the own unit is operating normally. The instruction execution process is a process for executing a user program or the like, and various operations are executed using the data acquired in the I / O refresh process executed in the previous cycle, and the I / O refresh process in the current cycle is executed. It is a process to generate the data to be output in. In the instruction execution process, a control signal is generated for an external device other than the other CPU unit, which is the control target of the PLC 10 (more accurately, the first CPU unit 100A or the second CPU unit 100B). The I / O refresh process is a process for executing data exchange with an external device and an external unit other than the duplicated CPU unit of the other party, and outputs the data generated in the command execution process of the current cycle, and then outputs the data. It is a process to acquire the data used for the instruction execution process of the cycle of. The control signal generated in the instruction execution process is output to the control target in the I / O refresh process.

As shown in FIG. 2, in each of the ACT (first CPU unit 100A) and the STB (second CPU unit 100B), the own unit executes each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. After completing the above, execute the "synchronization check process". In this synchronization check process, each of the ACT and STB monitors the status of the CPU unit of the other party (in other words, confirms), and if the ACT is abnormally stopped, the STB replaces the abnormally stopped ACT. , Take over the driving.

The "synchronous check process" is a process for confirming whether the CPU unit of the other party has completed the execution in the same manner as the own unit for the process in which the own unit has completed the execution, and the process completion of the CPU unit of the other party cannot be confirmed. If so, it is determined that an abnormality has occurred. For example, in the ACT, after each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process is completed, the STB executes each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. Confirm (determine) whether the is completed. For example, the STB completes each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process, and then the ACT executes each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. Confirm (determine) whether the is completed.

In the "synchronous check process", each of the ACT and STB "is a certain process" from the CPU unit of the other party after a predetermined time (= waiting time Tw) has elapsed since the own unit completed the execution of a certain process. Confirm that you have received the notification that "execution has been completed". Each of the ACT and STB cannot obtain the notification that the other CPU unit has "completed the execution of a certain process" after the waiting time Tw has elapsed since the own unit completed the execution of a certain process. And, it is determined that "an error has occurred in the duplicated CPU unit of the other party". When the first CPU unit 100A is an ACT and the second CPU unit 100B is an STB, when it is determined that an abnormality has occurred in the first CPU unit 100A, the second CPU unit 100B switches to the ACT and continues the operation. do.

As described above, when the length of the "waiting time Tw" is the same for the ACT (first CPU unit 100A) and the STB (second CPU unit 100B), if the performance Ab is different between the ACT and the STB, an erroneous judgment and an ACT are made. There is a problem that a delay in switching from to STB occurs. Therefore, each of the ACT and the STB executes the following processing to perform an accurate synchronization check processing without providing an unnecessary waiting time Tw even if the performance Abs of the two are different.

That is, first, a "reference CPU unit (reference CPU unit) of hardware" is assumed in advance, and the performance Ab (processing capacity) and processing time are defined in advance for this reference CPU unit. In the following description, the performance Ab of the reference CPU unit may be referred to as "performance Abb".

Then, information indicating the performance Ab of the own unit is given to each of the ACT and STB, for example, information indicating "how much the performance Ab the own unit has as compared with the reference CPU unit" (self). Machine performance information) is retained. When the ACT and the STB are duplicated in the PLC 10, each of the ACT and the STB grasps each other's performance Ab (the performance Ab of the other CPU unit relative to the performance Abb of the reference CPU unit). Then, each of the ACT and the STB flexibly sets the waiting time Tw for the synchronization check process based on each other's performance Ab that has been grasped. In the following description, the performance Ab of the own unit (the performance Ab of the own unit relative to the performance Abb of the reference CPU unit) may be expressed as "performance Abm". Similarly, the performance Ab of the CPU unit of the other party (the performance Ab of the CPU unit of the other party relative to the performance Abb of the reference CPU unit) may be expressed as "performance Aby".

Specifically, when each of the ACT and the STB is duplicated in the PLC 10, the waiting time Tw for the synchronization check process is set as follows. That is, when the performance Aby of the CPU unit of the other party to be duplicated is higher than the performance Abm of the own unit, that is, when the CPU unit of the other party to be duplicated has a faster processing execution speed than the own unit, the normal waiting time Set Two to the waiting time Tw. When the performance Aby of the CPU unit of the other party to be duplicated and the performance Abm of the own unit are equal, that is, when the execution speed of the processing is the same between the CPU unit of the other party to be duplicated and the own unit, the normal waiting time Two is set. Set the waiting time Tw. If the performance Aby of the CPU unit of the other party to be duplicated is lower than the performance Abm of the own unit, that is, if the CPU unit of the other party to be duplicated has a slower processing execution speed than the own unit, the waiting time Tw is set to the other party. Set according to the performance Aby of the CPU unit of.

For example, if the performance Abm of the own unit is twice the performance Abb of the reference CPU unit and the performance Aby of the other CPU unit to be duplicated is 1/2 times the performance Abb of the reference CPU unit, the performance Abm is the performance. It is four times as much as Aby. In that case, if the own unit takes "10 ms (milliseconds)" to execute a certain process that is the target of the synchronization check process, the CPU unit of the other party will take "40 ms". Waiting time Tw is set to "30ms + normal waiting time Two".

For example, if the performance Abm of the own unit is 1/2 of the performance Abb of the reference CPU unit and the performance Aby of the other CPU unit to be duplicated is twice the performance Abb of the reference CPU unit, the performance Abm is the performance. It is 1/4 times Aby. In that case, if the own unit takes "40 ms" to execute a certain process that is the target of the synchronization check process, the CPU unit of the other party needs "10 ms", so that the waiting time Tw of the own unit Is set to "normal waiting time Two".

Each of the ACT (first CPU unit 100A) and STB (second CPU unit 100B) flexibly sets the waiting time Tw of its own unit according to the difference in performance Ab between its own unit and the other CPU unit to be duplicated. ..

(Specific example of processing)
As shown in FIG. 2, when the first CPU unit 100A (ACT) and the second CPU unit 100B (STB) are duplicated in the PLC 10, the ACT and the STB each execute a "duplication process" separately from the normal cycle. do. That is, each of the ACT and STB executes the "duplication process" before the "self-diagnosis process, instruction execution process, and I / O refresh process" that are cyclically and repeatedly executed.

Each of the ACT and the STB grasps each other's performance Ab in the "duplication process" and becomes a duplication state. The performance information (own machine performance information) of each of the ACT and STB is written in the non-volatile memory included in each CPU unit, for example, at the time of production of each CPU unit. This own machine performance information is, for example, "the performance of the own unit with respect to the performance Abb of the reference CPU unit based on the performance Abb of the CPU unit of the specific hardware specifications (the above-mentioned" reference CPU unit "). Abm indicates what percentage of performance UP / DOWN. "

Each of the ACT and STB stores the performance information of its own unit in the non-volatile memory of each CPU unit as "own machine performance information". Each of the ACT and STB transfers this own machine performance information to each other in the duplication process, and the own machine performance information of the other CPU unit is used as "other machine performance information" in the non-volatile memory of each CPU unit. Store.

For example, the performance information of the own machine is 150% (that is, the execution speed (processing speed) of the processing is 1.5 times that of the reference CPU unit), and the performance information of the other machine is 75% (the processing speed is the reference CPU unit). If it is 0.75 times), the ACT grasps the following information. That is, the ACT grasps that the processing speed of the own unit (ACT) is "twice (= 1.5 times / 0.75 times)" the processing speed of the CPU unit (STB) of the other party.

For example, the performance information of the own machine is 75% (the processing speed is 0.75 times that of the reference CPU unit), and the performance information of the other machine is 150% (that is, the execution speed (processing speed) of the processing is the reference CPU unit. If it is 1.5 times), the STB grasps the following information. That is, it is understood that the processing speed of the own unit (STB) is "1/2 times (= 0.75 times / 1.5 times)" the processing speed of the CPU unit (ACT) of the other party.

In the "duplication process", the difference in performance Ab between the own unit and the CPU unit of the other party is grasped, and when the duplication state is reached, each of the ACT and STB uses this difference in performance Ab to wait for the own unit. Set Tw.

Each of the ACT and STB measures, for example, the execution time from the start of execution of the "instruction execution" process of FIG. 2 to the completion of execution in each CPU unit using an internal timer included in each CPU unit. Here, regarding the "instruction execution" process, assuming that the ACT execution time is "100 ms", the difference in performance Ab from the STB is "double" as described above, so the CPU unit (STB) of the other party is "200 ms". It will take.

Therefore, the ACT sets the period obtained by adding "100 ms (= 200 ms-100 ms)" to the normal waiting time Two as the waiting time Tw of the synchronization check process related to the "instruction execution" process of the own unit. In the example shown in FIG. 2, the ACT executes the standby process for a period of "100 ms" from the time when the execution of the "instruction execution" process in the own unit is completed, and then the synchronous check process related to the "instruction execution" process. Is running. That is, the ACT performs the "instruction execution" process from the CPU unit (STB) of the other party between the time when the execution of the "instruction execution" process in the own unit is completed and the time when "100 ms + normal waiting time Two" elapses. Determines whether or not to acquire the notification of the completion of execution of. Then, the ACT notifies the STB of the completion of the execution of the "instruction execution" process from the time when the execution of the "instruction execution" process in the own unit is completed until "100 ms + normal waiting time Two" elapses. If it cannot be acquired, it is determined that an abnormality has occurred in the STB.

The STB who grasps that "the CPU unit (ACT) of the other party has higher performance Ab or equal performance Ab (that is, the processing speed is faster or the same)" keeps the normal waiting time Two as it is. , Set as the waiting time Tw of the synchronization check process related to the "command execution" process of the own unit. In the example shown in FIG. 2, the STB executes the synchronization check process related to the "instruction execution" process as soon as the execution of the "instruction execution" process in the own unit is completed. That is, the STB completes the execution of the "instruction execution" process from the CPU unit (ACT) of the other party between the time when the execution of the "instruction execution" process in the own unit is completed and the time when the normal waiting time Two elapses. Determine whether to get the notification of. Then, the STB cannot obtain the notification of the execution completion of the "instruction execution" process from the ACT between the time when the execution of the "instruction execution" process in the own unit is completed and the time when the normal waiting time Two elapses. , It is determined that an abnormality has occurred in the ACT. When it is determined that an abnormality has occurred in the ACT (first CPU unit 100A), the STB (second CPU unit 100B) switches its own unit to the ACT and continues the operation.

§2. Configuration Example The first CPU unit 100A and the second CPU unit 100B, which have been outlined with reference to FIG. 2, will be described in detail with reference to FIG. 1.

FIG. 1 is a block diagram showing a main configuration of a PLC 10 including a first CPU unit 100A and a second CPU unit 100B CPU unit according to the first embodiment of the present invention. As illustrated in FIG. 1, the PLC 10 includes a first CPU unit 100A and a second CPU unit 100B that are duplicated in the PLC 10. Each of the first CPU unit 100A and the second CPU unit 100B is a functional unit that controls the control of the entire PLC 10.

The PLC 10 may further include a functional unit (not shown in FIG. 1). The PLC 10 further includes, for example, a power supply unit (not shown) that supplies power to the entire PLC 10 including the first CPU unit 100A and the second CPU unit 100B. The PLC 10 is also not shown, such as an input unit for inputting signals of switches and sensors mounted at appropriate positions in production equipment and equipment, an output unit for outputting control signals to actuators, and a communication unit for connecting to a communication network. It may include a functional unit.

As described above, each of the first CPU unit 100A and the second CPU unit 100B repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. In the I / O refresh process, various input signals acquired by the input unit or the like are taken into the I / O memory of each CPU unit (IN refresh), and the processing result of the instruction execution process is written to the I / O memory. It includes a process (OUT refresh) to output to an output unit or the like. That is, the I / O refresh process is cyclic between "each of the first CPU unit 100A and the second CPU unit 100B" and "an external unit and an external device other than the first CPU unit 100A and the second CPU unit 100B". Data exchange. In the instruction execution process, various control signals output by the controller PLC10 to the control target are generated. For example, a logical operation using an input signal taken into the I / O memory by IN refresh based on a user program. Is executed and a control signal is generated.

In the PLC 10, in order to improve the safety and reliability of the control system controlled by the PLC 10, the first CPU unit 100A and the second CPU unit 100B are duplicated, and both are connected by, for example, an inter-CPU bus. If there is no abnormality in both the first CPU unit 100A and the second CPU unit 100B, the first CPU unit 100A and the second CPU unit 100B start executing the same processing (each of the self-diagnosis processing, the instruction execution processing, and the I / O refresh processing) at the same timing. For example, if there is no abnormality in both the first CPU unit 100A and the second CPU unit 100B, the execution of the same user program using the same input signal is started at the same timing.

Of the first CPU unit 100A and the second CPU unit 100B, one is an executing CPU unit (ACT) and the other is a standby CPU unit (STB). As described above, in the present specification, an example of "the first CPU unit 100A is an ACT and the second CPU unit 100B is an STB" will be described, but "the first CPU unit 100A is an STB and the second CPU unit 100B is an STB". The same applies to the case of "ACT".

The first CPU unit 100A, which is an ACT, actually performs cyclic processing, reads and writes to the memory, and sends and receives control data (I / O data) to and from an external I / O device or the like. It controls the control system controlled by the PLC 10. The second CPU unit 100B, which is an STB, executes the same user program as that executed by the first CPU unit 100A, which is an ACT, while waiting (that is, while no abnormality has occurred in the first CPU unit 100A, which is an ACT). do. However, the second CPU unit 100B, which is an STB, does not output the execution result (calculation execution result) of the executed user program to an external I / O device or the like. Further, the second CPU unit 100B, which is an STB, receives processing results (calculation execution results and various input signals acquired by the first CPU unit 100A, which is an ACT) from the first CPU unit 100A, which is an ACT. Then, the second CPU unit 100B, which is an STB, updates the contents of the memory of its own unit according to the processing result or the like received from the first CPU unit 100A, which is an ACT. As a result, the sameness of the contents of the memories of the second CPU unit 100B, which is an STB, and the first CPU unit 100A, which is an ACT, is ensured.

When the first CPU unit 100A, which is an ACT, fails, the second CPU unit 100B, which is an STB, is switched to the first CPU unit 100A, which is an ACT, and an operation such as actual control is performed. By duplicating the first CPU unit 100A and the second CPU unit 100B in the PLC10, even if the first CPU unit 100A, which is an ACT, fails, the entire PLC10 does not stop immediately and can be continuously operated. , Improves reliability.

(Details of CPU unit)
As shown in FIG. 1, the PLC 10 includes, in addition to the first CPU unit 100A and the second CPU unit 100B, which are duplicated in the PLC 10, both have a common register 200 capable of executing writing and reading, respectively. In order to ensure the conciseness of the description, the configuration not directly related to the present embodiment is omitted from the description and the block diagram. However, according to the actual situation of implementation, the PLC 10 may have the omitted configuration.

The common register 200 includes a first register 210 and a second register 220.

The first register 210 uses the first CPU unit 100A to "execute a certain process (self-diagnosis process, instruction execution process, and I / O refresh process) by the own unit (that is, the first CPU unit 100). Information to the effect that "completed" is written. The information written in the first register 210 by the first CPU unit 100A is read by the second CPU unit 100B.

The second register 220 uses the second CPU unit 100B to "execute a certain process (self-diagnosis process, instruction execution process, and I / O refresh process) by the own unit (that is, the second CPU unit 100B). Information to the effect that "completed" is written. The information written in the second register 220 by the second CPU unit 100B is read by the first CPU unit 100A.

In addition to the storage unit 130A, the first CPU unit 100A includes a capacity acquisition unit 110A, a processing execution unit 120A, a waiting time setting unit 160A, and a determination unit 170A as functional blocks. The storage unit 130A stores the other functional power table 140A and the self-functional power table 150A.

In addition to the storage unit 130B, the second CPU unit 100B includes a capacity acquisition unit 110B, a processing execution unit 120B, a waiting time setting unit 160B, and a determination unit 170B as functional blocks. The storage unit 130B stores the other functional power table 140B and the self-functional power table 150B.

In the following, when it is not necessary to distinguish each of the ability acquisition unit 110A and the ability acquisition unit 110B, it is simply referred to as "ability acquisition unit 110". Similarly, when it is not necessary to distinguish each of the processing execution unit 120A and the processing execution unit 120B, it is simply referred to as "processing execution unit 120". When it is not necessary to distinguish each of the storage unit 130A and the storage unit 130B, it is simply referred to as "storage unit 130". When it is not necessary to distinguish each of the other functional power table 140A and the other functional power table 140B, it is simply referred to as "other functional power table 140". When it is not necessary to distinguish between the self-functional power table 150A and the self-functional power table 150B, it is simply referred to as "self-functional power table 150". When it is not necessary to distinguish between the waiting time setting unit 160A and the waiting time setting unit 160B, it is simply referred to as "waiting time setting unit 160". When it is not necessary to distinguish each of the determination unit 170A and the determination unit 170B, it is simply referred to as "determination unit 170".

Each functional block such as the capacity acquisition unit 110, the processing execution unit 120, the waiting time setting unit 160, and the determination unit 170 has, for example, a CPU (central processing unit) or the like having a ROM (read only memory) or NVRAM (non-). It can be realized by reading a program stored in a storage device (storage unit 130) realized by a Volatile random access memory) or the like into a RAM (random access memory) or the like (not shown) and executing the program.

(Details of functional blocks)
The capacity acquisition unit 110 acquires information (“performance information”) indicating the performance Aby (processing capacity) of the CPU unit of the other party to be duplicated with reference to the self-functioning power table 150 of the CPU unit of the other party. The capacity acquisition unit 110 stores the acquired performance information (performance information of another machine) of the other party's CPU unit in the other function power table 140 of the own unit.

In particular, the capability acquisition unit 110 has the “duplication process” illustrated in FIG. 2 once before the process execution unit 120 repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. To acquire the performance information of other machines.

FIG. 3 is a diagram illustrating a specific example of a process of "acquiring performance information indicating the performance Aby of the CPU unit of the other party to be duplicated", which is executed once in the "duplication process". As shown in FIG. 3, the capability acquisition unit 110A acquires the performance information indicating the performance Aby of the second CPU unit 100B with reference to the self-functioning power table 150B, and acquires the performance information of the second CPU unit 100B (other machine). Performance information) is stored in the other functional power table 140A. Further, the capability acquisition unit 110B acquires the performance information indicating the performance Aby of the first CPU unit 100A with reference to the self-functional power table 150A, and obtains the acquired performance information (other machine performance information) of the first CPU unit 100A. It is stored in the other functional power table 140B.

The process execution unit 120 repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order, and when the execution of each process is completed, "the own unit has completed the execution of each process". This is written in the common register 200.

Further, when the process execution unit 120 completes the execution of each process, the process execution unit 120 notifies the waiting time setting unit 160 and the determination unit 170 that "the own unit has completed the execution of each process". The process execution unit 120 informs the waiting time setting unit 160 that "the own unit has completed the execution of each process" and "execution time of each process (time from the start of execution to the completion of execution of each process)". You may notify. That is, the process execution unit 120 may use an internal timer to time the "execution time of each process" and notify the timed-out "execution time of each process" to the waiting time setting unit 160.

<Writing the execution completion of the process> When the process execution unit 120 completes each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process, that effect (that is, "the own unit performs the process". Has been completed) is written in the common register 200. That is, the process execution unit 120A that has completed the execution of the self-diagnosis process writes to the first register 210 that "the own unit has completed the execution of the self-diagnosis process", and completes the execution of the self-diagnosis process. The 120 writes to the second register 220 that "the own unit has completed the execution of the self-diagnosis process". The process execution unit 120A that has completed the execution of the instruction execution process writes to the first register 210 that "the own unit has completed the execution of the instruction execution process", and the process execution unit 120B that has completed the execution of the instruction execution process is , "The own unit has completed the execution of the instruction execution process" is written in the second register 220. The process execution unit 120A that has completed the execution of the I / O refresh process writes to the first register 210 that "the own unit has completed the execution of the I / O refresh process", and completes the execution of the I / O refresh process. The processing execution unit 120B writes to the second register 220 that "the own unit has completed the execution of the I / O refresh processing".

<Timing of Processing Execution Start> While the first CPU unit 100A and the second CPU unit 100B are duplicated, the processing execution unit 120 executes each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. Is started at the following timing. In other words, while it is not determined that an abnormality has occurred in each of the first CPU unit 100A and the second CPU unit 100B, the processing execution unit 120 executes each of the self-diagnosis processing, the instruction execution processing, and the I / O refresh processing. Is started at the following timing.

That is, the process execution unit 120 executes each of the self-diagnosis process, the instruction execution process, and the I / O refresh process in the synchronous check process after the execution of the previous process is completed, and the first CPU unit 100A and the second CPU unit. It starts after the normality with 100B is confirmed.

Specifically, in the synchronization check process after the execution of the self-diagnosis process is completed, the process execution unit 120 starts executing the instruction execution process after the normality of the first CPU unit 100A and the second CPU unit 100B is confirmed. .. In the synchronization check process after the execution of the instruction execution process is completed, the process execution unit 120 starts executing the I / O refresh process after the normality of the first CPU unit 100A and the second CPU unit 100B is confirmed. After the normality of the first CPU unit 100A and the second CPU unit 100B is confirmed in the synchronization check process after the execution of the I / O refresh process is completed, the process execution unit 120 starts executing the self-diagnosis process in the next cycle. do.

The waiting time setting unit 160 refers to the other functional power table 140 to acquire the performance information of the other machine, and refers to the self-functional power table 150 to acquire the performance information of the own machine. Further, the waiting time setting unit 160 acquires from the processing execution unit 120 that "the own unit has completed the execution of each process". The waiting time setting unit 160 together with the fact that "the own unit has started the execution of each process" acquired from the process execution unit 120 before acquiring "the own unit has completed the execution of each process". , Calculate the execution time of each process. That is, the waiting time setting unit 160 is based on the time when "the own unit starts executing each process" timed by the internal timer and the time when "the own unit completes the execution of each process" timed by the internal timer. Calculate the execution time of each process. The execution time of each process may be timed by the process execution unit 120 using an internal timer, and may be notified from the process execution unit 120 to the waiting time setting unit 160.

The waiting time setting unit 160 calculates the "waiting time Tw" for the synchronization check processing for each processing from the acquired other machine performance information, the own machine performance information, and the execution time of each processing, and the calculated waiting time. Notify the determination unit 170 of the time Tw. Specifically, the waiting time setting unit 160 uses the performance information of other machines, the performance information of its own machine, and the execution time of each process to "wait" for the synchronization check process for each process as follows. "Time Tw" is calculated.

That is, when the "performance Aby of the other party's CPU unit to be duplicated" shown in the performance information of the other machine is higher than the "performance Abm of the own unit" shown in the performance information of the own machine, the waiting time setting unit 160 is "normally". "Waiting time Tw" is defined as "waiting time Tw". Further, when the performance Aby of the CPU unit of the other party to be duplicated is equal to the performance Abm of the own unit, the waiting time setting unit 160 sets "normal waiting time Two" to "waiting time Tw".

The "normal waiting time Two" is a period common to the first CPU unit 100A and the second CPU unit 100B, which has a predetermined length. For example, it is set at the time of factory shipment of each unit and can be updated by the user. It is a period. The "normal waiting time Two" is a period set on the assumption that the performance Ab of the first CPU unit 100A and the second CPU unit 100B is equal.

When the performance Aby of the CPU unit of the other party to be duplicated is lower than the performance Abm of the own unit, the waiting time setting unit 160 executes each process to the value obtained by dividing the performance Abm of the own unit by the performance Aby of the CPU unit of the other party. The period multiplied by the time is defined as the adjustment waiting time Ta. Then, the waiting time setting unit 160 sets the "period in which the adjustment waiting time Ta is added to the normal waiting time Two (that is," normal waiting time Two + adjustment waiting time Ta ")" as "waiting time Tw".

The determination unit 170 is the CPU of the other party for the processing completed by the processing execution unit 120 from the time when the execution of each processing by the processing execution unit 120 is completed until the waiting time Tw notified from the waiting time setting unit 160 elapses. Determines if the unit completes execution (synchronous check process). For example, the determination unit 170 refers to the common register 200 when the waiting time Tw has elapsed from the time when the own unit has completed the execution of each process, and duplicates the certain process for which the own unit has completed the execution. Check if the execution of the CPU unit of the other party is completed.

The determination unit 170 notified of "normal waiting time Two + adjustment waiting time Ta" as the waiting time Tw executes the waiting process from the time when "the own unit completes the execution of each process" until the adjustment waiting time Ta occurs. .. Then, the determination unit 170 executes the synchronization check process after the execution of the standby process is completed (that is, after the adjustment waiting time Ta has elapsed from the time when the own unit has completed the execution of each process). That is, after the execution of the standby process is completed, the determination unit 170 can confirm that the CPU unit of the other party has completed the execution of the process whose execution has been completed by the own unit by the time the normal waiting time Two elapses. Is it judged? In other words, the determination unit 170 determines whether the processing completed by the own unit can be confirmed to be completed by the CPU unit of the other party from the time when the execution of the standby processing is completed until the normal waiting time Two elapses. The "time when the execution of the standby process is completed" is "the time when the execution of a certain process whose execution is completed by the own unit is expected to be completed in the CPU unit of the other party".

The determination unit 170 notified of the "normal waiting time Two" as the waiting time Tw immediately executes the synchronization check process when "the own unit completes the execution of each process". That is, the determination unit 170 determines "whether it is possible to confirm that the CPU unit of the other party has completed the execution of the process for which the own unit has completed execution by the time the normal waiting time Two elapses". In other words, the determination unit 170 determines whether the processing completed by the own unit can be confirmed by the CPU unit of the other party from the time when the execution of the own unit is completed until the normal waiting time Two elapses.

The determination unit 170A refers to the second register 220 of the common register 200, and indicates whether or not there is a writing that "execution by the processing execution unit 120B has been completed" for a certain process for which the processing execution unit 120A has completed execution. confirm. If the determination unit 170A does not write in the second register 220 that "execution by the process execution unit 120B has been completed" for a certain process for which the process execution unit 120A has completed execution, an error occurs in the second CPU unit 100B. Judge that it has occurred.

The determination unit 170B refers to the first register 210 of the common register 200, and indicates whether or not there is a writing that "execution by the processing execution unit 120A has been completed" for a certain process for which the processing execution unit 120B has completed execution. confirm. If the determination unit 170B does not write in the first register 210 that "execution by the process execution unit 120A has been completed" for a certain process for which the process execution unit 120B has completed execution, an error occurs in the first CPU unit 100A. Judge that it has occurred.

(Details of memory)
The storage unit 130 is a storage device that stores various data used by each of the first CPU unit 100A and the second CPU unit 100B. In the storage unit 130, each of (1) a control program, (2) an OS program, and (3) a first CPU unit 100A and a second CPU unit 100B executed by each of the first CPU unit 100A and the second CPU unit 100B The application program for executing the various functions possessed by the application program and (4) various data to be read when the application program is executed may be stored non-temporarily. The data of (1) to (4) above may be, for example, ROM (read only memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (registered trademark) (Electrically EPROM), HDD (Hard Disc Drive), or the like. Stored in a non-volatile storage device. Each of the first CPU unit 100A and the second CPU unit 100B may include a temporary storage unit (not shown). The temporary storage unit is a so-called working memory that temporarily stores data used for calculation, calculation results, etc. in the process of various processes executed by each of the first CPU unit 100A and the second CPU unit 100B, and is a RAM (Random). It consists of volatile storage devices such as Access Memory). Which data is stored in which storage device is appropriately determined from the purpose of use, convenience, cost, physical restrictions, etc. of each of the first CPU unit 100A and the second CPU unit 100B. The storage unit 130 further stores the other functional power table 140 and the self-functional power table 150.

In the other functional power table 140, the performance information of the other machine, which is the information indicating the performance Aby of the CPU unit of the other party to be duplicated, is stored. As described with reference to FIG. 3, the capability acquisition unit 110 transfers the performance information of the other machine acquired by referring to the self-functional power table 150 of the other party's CPU unit to be duplicated in the other functional power table 140 of the own unit. Store.

The self-functioning power table 150 stores the own-machine performance information, which is information indicating the performance Abm of the own unit. For example, "how much performance Ab (processing capacity) the own unit has as compared with the reference CPU unit). The performance information of the own machine indicating "Is it equipped?" Is stored. The own machine performance information is stored in the self-functional power table 150 at the time of shipment from each of the first CPU unit 100A and the second CPU unit 100B, for example.

(Arrangement of CPU units)
In order to facilitate understanding of each of the first CPU unit 100A and the second CPU unit 100B whose configurations have been described with reference to FIG. 1, they are arranged as follows. That is, each of the first CPU unit 100A and the second CPU unit 100B is a CPU unit duplicated in the PLC 10 (controller), and includes a waiting time setting unit 160 (setting unit) and a determination unit 170. The waiting time setting unit 160 sets the waiting time Tw in consideration of the ratio between the performance Abm (processing capacity) of the own unit and the performance Aby of the CPU unit of the other party to be duplicated. If the determination unit 170 cannot confirm the completion of the execution of the processing of the other CPU unit from the time when the execution of the processing in the own unit is completed until the waiting time Tw set by the waiting time setting unit 160 elapses, the other party's CPU unit It is determined that an abnormality has occurred in the CPU unit.

According to the above configuration, each of the first CPU unit 100A and the second CPU unit 100B sets the waiting time Tw in consideration of the ratio of the performance Ab (processing capacity) between the own unit and the other CPU unit. Then, each of the first CPU unit 100A and the second CPU unit 100B uses the set waiting time Tw to determine the synchronization between the own unit and the CPU unit of the other party (that is, the match of the processing completed).

For example, when the performance Ab of the other CPU unit is higher than that of the own unit (that is, the processing execution speed is faster), each of the first CPU unit 100A and the second CPU unit 100B is predetermined as a waiting time Tw. Set the normal waiting time Two. When the performance Ab of the other CPU unit and the own unit is the same, each of the first CPU unit 100A and the second CPU unit 100B sets a predetermined "normal waiting time Two" as the waiting time Tw.

If the CPU unit of the other party has a higher performance Ab than the own unit, the CPU unit of the other party should have already completed the execution of the certain process when the own unit completes the execution of a certain process. Further, when the performance Ab is equal between the CPU unit of the other party and the own unit, the CPU unit of the other party should complete the execution of the certain process when the own unit completes the execution of a certain process.

Therefore, even if the CPU unit of the other party has a higher performance Ab than the own unit, each of the first CPU unit 100A and the second CPU unit 100B can set the normal waiting time Tw as the waiting time Tw of the other party. It is possible to accurately determine whether or not an abnormality has occurred in the CPU unit.

For example, when the performance Ab of the other CPU unit is lower than that of the own unit, each of the first CPU unit 100A and the second CPU unit 100B has a waiting time Tw of "normal waiting time Two plus adjustment waiting time Ta". Set the period. The adjustment waiting time Ta is set in consideration of the difference in performance Ab between the own unit and the CPU unit of the other party. For example, "the difference between the time when the execution of the process in the own unit is completed and the time when the execution of the process is expected to be completed in the CPU unit of the other party" is defined as the adjustment waiting time Ta.

When the performance Ab of the other CPU unit is lower than that of the own unit, the other CPU unit has not yet completed the execution of the certain process when the own unit completes the execution of a certain process. Therefore, each of the first CPU unit 100A and the second CPU unit 100B waits until "a time when the execution of the process in the other CPU unit is expected to be completed (execution completion expected time)". Then, each of the first CPU unit 100A and the second CPU unit 100B determines whether or not the execution completion of the process in the other CPU unit can be confirmed from the time when the execution completion is predicted until the normal waiting time Two elapses. That is, each of the first CPU unit 100A and the second CPU unit 100B is the other party from the time when the execution of the process in the own unit is completed until the "period in which the adjustment waiting time Ta is added to the normal waiting time Two" elapses. It is determined whether or not the execution completion of the process can be confirmed in the CPU unit of the above.

Therefore, even if the performance Ab of the other CPU unit is lower than that of the own unit, each of the first CPU unit 100A and the second CPU unit 100B sets the waiting time Tw to "adjustment waiting time Ta to normal waiting time Two". By setting the "added period", the above determination can be accurately executed.

As described above, each of the first CPU unit 100A and the second CPU unit 100B has a difference in performance Ab between the own unit and the other CPU unit even if the performance Ab does not match between the own unit and the other CPU unit. It is effective that an appropriate waiting time Tw can be set in consideration of the above. That is, each of the first CPU unit 100A and the second CPU unit 100B performs the synchronization check process without providing an unnecessary waiting time Tw in consideration of the difference in performance Ab between the CPU unit of the other party to be duplicated and the own unit. It has the effect of being able to be done accurately.

In each of the first CPU unit 100A and the second CPU unit 100B, the process (process to be the target of the synchronization check process) includes a self-diagnosis process, an instruction execution process, and an I / O refresh process. The self-diagnosis process is a process of diagnosing whether or not there is an abnormality in the hardware of the own unit. The instruction execution process is a process of generating a signal for controlling "an external device and an external unit other than the CPU unit of the other party". The I / O refresh process is a process of exchanging data with "an external device and an external unit other than the other CPU unit". The waiting time setting unit 160 sets the waiting time Tw for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. The determination unit 170 executes the determination, that is, the synchronization check process, for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process.

Each of the first CPU unit 100A and the second CPU unit 100B synchronizes the self-diagnosis process, the instruction execution process, and the I / O refresh process with the CPU unit of the other party (that is, the process of completing the execution). Match) is determined.

Each of the first CPU unit 100A and the second CPU unit 100B determines the synchronization between the own unit and the other CPU unit at the timing of completion of each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process. It has the effect of being able to.

Each of the first CPU unit 100A and the second CPU unit 100B executes the duplication process once before repeatedly executing the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. Each of the first CPU unit 100A and the second CPU unit 100B acquires the performance Aby of the other CPU unit from the other CPU unit in the duplication process.

According to the above configuration, each of the first CPU unit 100A and the second CPU unit 100B repeats the performance Aby of the other CPU unit, the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. Get it once before executing. Then, each of the first CPU unit 100A and the second CPU unit 100B takes into consideration the ratio between the acquired performance Aby of the other CPU unit and the performance Abm of the own unit, and waits for the determination for each of the processes. Set Tw.

Each of the first CPU unit 100A and the second CPU unit 100B takes into consideration the performance Aby of the other CPU unit acquired before repeatedly executing each of the processes, and waits for the determination of each process. It has the effect of being able to set Tw.

§3. Operation Example Each of the first CPU unit 100A and the second CPU unit 100B executes the following processing as shown in FIG. That is, each of the first CPU unit 100A and the second CPU unit 100B repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. Specifically, the process execution unit 120 of each unit repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. Further, each of the first CPU unit 100A and the second CPU unit 100B (particularly, the capacity acquisition unit 110 of each unit) before repeatedly executing the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. The duplication process is executed once. Each of the first CPU unit 100A and the second CPU unit 100B acquires the performance information of another machine indicating the performance Aby of the other CPU unit to be duplicated in the duplication process.

When each unit (particularly, the process execution unit 120 of each unit) completes the execution of each process of the self-diagnosis process, the instruction execution process, and the I / O refresh process, "the own unit has completed the execution of each process." Is written in the common register 200.

Each unit (particularly, the waiting time setting unit 160 of each unit) is used for synchronization check processing for each processing from the performance information of other machines, the performance information of own machine, and the execution time of each processing completed by the own unit. Set the "waiting time Tw" of.

Specifically, the waiting time setting unit 160 calculates "adjustment waiting time Ta calculated in consideration of the ratio between the performance Abm of the own unit and the performance Aby of the CPU unit of the other party to be duplicated" for each process. .. Then, the waiting time setting unit 160 adds the "adjustment waiting time Ta calculated for each process" to the "normal waiting time Two for each process" for the synchronization check process for each process. Set as "waiting time Tw".

When "Abm / Aby" is "1" or less, the waiting time setting unit 160 sets "adjustment waiting time Ta = 0" for each process. When "Abm / Aby" is larger than "1", the waiting time setting unit 160 sets the "adjustment waiting time Ta" of each process as the value obtained by multiplying the execution time of each process by "Abm / Aby".

Each unit (particularly, the determination unit 170 of each unit) executes the synchronization check process after each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process by the own unit is completed. That is, the determination unit 170 refers to the common register 200, and the CPU unit of the other party executes the processing completed by the own unit from the time when the execution of each process by the own unit is completed until the waiting time Tw elapses. Determine if it is complete.

The synchronization check process is a process of mutually monitoring the status of the CPU units of the other party to be duplicated. Specifically, the synchronization check process is a process of confirming (determining) whether or not the CPU unit of the other party to be duplicated has completed the execution of the process whose execution has been completed in the own unit.

In the synchronization check process, if synchronization cannot be confirmed, that is, if execution completion cannot be confirmed in the other CPU unit for the process whose execution has been completed in the own unit, the duplication of the first CPU unit 100A and the second CPU unit 100B is eliminated. Then, for example, in the STB that determines that an abnormality has occurred in the ACT, the own unit continues to operate in place of the ACT.

When synchronization can be confirmed in the synchronization check process, each unit (particularly, the process execution unit 120 of each unit) performs the next process of "the process in which the execution completion by the own unit and the CPU unit of the other party can be confirmed in the synchronization check process". Starts executing. Specifically, the synchronization check process is executed as shown below.

That is, when the process execution unit 120A completes the execution of a certain process, the unit (that is, the process execution unit 120A) has completed the execution of the process in the first register 210 of the common register 200. To write. The determination unit 170B recognizes that the first CPU unit 100A has completed the execution of a certain process by reading the first register 210. Further, when the processing execution unit 120B completes the execution of a certain processing, the second register 220 of the common register 200 indicates that "the own unit (that is, the processing execution unit 120B) has completed the execution of the certain processing". To write. The determination unit 170A recognizes that the second CPU unit 100B has completed the execution of a certain process by reading the second register 220. When the determination unit 170A and the determination unit 170B each recognize "the execution completion of a certain process by the CPU unit of the other party", the process execution unit 120A and the process execution unit 120B each perform the next process of the certain process. Starts executing.

The "processes executed by each of the first CPU unit 100A and the second CPU unit 100B" described so far can be organized as follows. That is, the "process executed by each of the first CPU unit 100A and the second CPU unit 100B" is a control method of the CPU unit duplicated in the PLC 10 (controller), and includes a setting step and a determination step. In the setting step, the waiting time Tw is set in consideration of the ratio between the performance Abm of the own unit and the performance Aby of the CPU unit of the other party to be duplicated. In the determination step, if it is not possible to confirm the completion of execution of the process in the CPU unit of the other party from the time when the execution of the process in the own unit is completed until the waiting time Tw set in the setting step elapses, the CPU unit of the other party is informed. Judge that an abnormality has occurred.

According to the above method, in the control method, synchronization between the own unit and the CPU unit of the other party is performed by using the waiting time Tw set in consideration of the ratio of the performance Ab between the own unit and the CPU unit of the other party. That is, the match of the processed processing completed) is determined.

For example, when the CPU unit of the other party has a higher performance Ab (that is, the execution speed of processing is faster) than the own unit, the control method uses a predetermined "normal waiting time Two" as the waiting time Tw. Set. Further, when the performance Ab is equal between the CPU unit of the other party and the own unit, the control method sets a predetermined "normal waiting time Two" as the waiting time Tw.

If the CPU unit of the other party has a higher performance Ab than the own unit, the CPU unit of the other party should have already completed the execution of the certain process when the own unit completes the execution of a certain process. Further, when the performance Ab is equal between the CPU unit of the other party and the own unit, the CPU unit of the other party should complete the execution of the certain process when the own unit completes the execution of a certain process.

Therefore, even if the CPU unit of the other party has a higher performance Ab than the own unit, each of the first CPU unit 100A and the second CPU unit 100B can set the normal waiting time Tw as the waiting time Tw of the other party. It is possible to accurately determine whether or not an abnormality has occurred in the CPU unit.

For example, when the CPU unit of the other party has a lower performance Ab than the own unit (that is, the execution speed of the process is slower), the control method uses the waiting time Tw as "the difference between the normal waiting time Two and the performance Ab". The period in which the adjustment waiting time Ta is added in consideration of the above is set. Specifically, the "difference between the time when the execution of the process in the own unit is completed and the time when the execution of the process in the other CPU unit is expected to be completed" is defined as the adjustment waiting time Ta.

When the performance Ab of the other CPU unit is lower than that of the own unit, the other CPU unit has not yet completed the execution of the certain process when the own unit completes the execution of a certain process. Therefore, the control method waits until "a time when the execution of the process is expected to be completed in the CPU unit of the other party", and then waits until the "normal waiting time Two" elapses, and then the process in the CPU unit of the other party. Judge whether the execution completion of is confirmed. That is, in the control method, the execution of the processing in the CPU unit of the other party elapses from the time when the execution of the processing in the own unit is completed until the "period in which the adjustment waiting time Ta is added to the normal waiting time Two" elapses. Determine if completion can be confirmed.

Therefore, even if the performance Ab of the CPU unit of the other party is lower than that of the own unit, the control method sets "the period in which the adjustment waiting time Ta is added to the normal waiting time Two" as the waiting time Tw. Therefore, the above determination can be accurately executed.

As described above, the control method has an appropriate waiting time in consideration of the difference in performance Ab between the own unit and the CPU unit of the other party even if the performance Ab does not match between the own unit and the CPU unit of the other party. It has the effect of being able to set Tw. That is, the control method can accurately perform the synchronization check process without providing an unnecessary waiting time Tw in consideration of the difference in performance Ab between the CPU unit of the other party to be duplicated and the own unit. It works.

[Embodiment 2]
The other embodiments of the present invention will be described below with reference to FIGS. 4 to 7. In order to ensure the conciseness of the description, only the configuration (processing procedure and processing content) different from the first embodiment will be described. That is, all the configurations and the like described in the first embodiment can be included in the present embodiment. Further, the definitions of the terms described in the first embodiment are the same.

In the first embodiment, the first CPU unit 100A and the second CPU unit 100B duplicated in the PLC 10 have one type of performance Aby of the other CPU unit used to set the "waiting time Tw" of the own unit. ..

On the other hand, the first CPU unit 300A and the second CPU unit 300B duplicated in the PLC 20 according to the present embodiment have a plurality of performance Abys of the other CPU unit used to set the "waiting time Tw" of the own unit. Is. The details will be described below.

FIG. 5 is a diagram showing an example of a hardware configuration that realizes each of the first CPU unit 300A and the second CPU unit 300B. That is, each of the first CPU unit 300A and the second CPU unit 300B is realized by using the memory 410, the CPU 420 (microcomputer), and the dedicated LSI (Large Scale Integration) 430. The dedicated LSI is also called an "ASIC (Application Specific Integrated Circuit)", and an FPGA (Field Programmable Gate Array) may be used instead of the dedicated LSI.

Each of the first CPU unit 300A and the second CPU unit 300B repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order, similarly to each of the first CPU unit 100A and the second CPU unit 100B. .. For example, the self-diagnosis process is mainly executed by the CPU 420, the instruction execution process is mainly executed by the dedicated LSI 430, and the I / O refresh process is mainly executed by the CPU 420 via the dedicated LSI 430.

When the hardware in which the self-diagnosis process, the instruction execution process, and the I / O refresh process are mainly executed is different, the performance Ab may differ between the first CPU unit 300A and the second CPU unit 300B for each process. .. For example, the CPU 420 of the first CPU unit 300A may have a higher performance Ab than the CPU 420 of the second CPU unit 300B, and the dedicated LSI 430 of the first CPU unit 300A may have a lower performance Ab than the dedicated LSI 430 of the second CPU unit 300B. In this case, the first CPU unit 300A completes the execution of the self-diagnosis process earlier than the second CPU unit 300B, and the first CPU unit 300A completes the execution of the instruction execution process later than the second CPU unit 300B.

Therefore, each of the first CPU unit 300A and the second CPU unit 300B grasps the performance Ab of the own unit and the other CPU unit for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process that are repeatedly executed. .. Then, each of the first CPU unit 300A and the second CPU unit 300B sets the "waiting time Tw" at the time of the synchronization check processing for each processing by using the performance Ab of the own unit and the other CPU unit related to each processing. do. The details will be described below.

(Details of CPU unit)
FIG. 4 is a block diagram showing a main configuration of the PLC 20 including the first CPU unit 300A and the second CPU unit 300B. Like the PLC 10, the PLC 20 may include a power supply unit, an input unit, an output unit, and a functional unit (not shown) such as a communication unit.

Each of the first CPU unit 300A and the second CPU unit 300B is a functional unit that controls the control of the entire PLC 10 like each of the first CPU unit 100A and the second CPU unit 100B. The first CPU unit 300A and the second CPU unit 300B are duplicated in the PLC 20. That is, one of the first CPU unit 300A and the second CPU unit 300B becomes the CPU unit (ACT) of the executing system, and the other becomes the CPU unit (STB) of the standby system, and monitors the state of each other. When it is determined that an abnormality has occurred in the ACT in the synchronization check process, the STB switches its own unit to the ACT instead of the CPU unit which was the ACT until then, and continues the operation. In the present embodiment, an example of "the first CPU unit 300A is an ACT and the second CPU unit 300B is an STB" will be described, but "the first CPU unit 300A is an STB and the second CPU unit 300B is an ACT". The same applies to the case.

As shown in FIG. 4, the PLC 20 includes, in addition to the first CPU unit 300A and the second CPU unit 300B, which are duplicated in the PLC 20, a common register 200 in which both can execute writing and reading, respectively. Since the common register 200 has already been described, the details will be omitted here.

In order to ensure the conciseness of the description, the configuration not directly related to the present embodiment is omitted from the description and the block diagram. However, according to the actual situation of implementation, the PLC 10 may have the omitted configuration.

In addition to the storage unit 330A, the first CPU unit 300A includes a capacity acquisition unit 310A, a processing execution unit 120A, a waiting time setting unit 360A, and a determination unit 370A as functional blocks. The storage unit 330A stores the other functional power table 340A and the self-functional power table 350A.

The waiting time setting unit 360A includes a first waiting time setting unit 361A, a second waiting time setting unit 362A, and a third waiting time setting unit 363A, and the determination unit 370A includes a first determination unit 371A and a second determination unit 372A. The third determination unit 373A is included. The other functional force table 340A includes a first other functional force table 341A, a second other functional force table 342A, and a third other functional force table 343A. The self-functional power table 350A includes a first self-functional power table 351A, a second self-functional power table 352A, and a third self-functional power table 353A.

In addition to the storage unit 330B, the second CPU unit 300B includes a capacity acquisition unit 310B, a processing execution unit 120B, a waiting time setting unit 360B, and a determination unit 370B as functional blocks. The storage unit 330B stores the other functional power table 340B and the self-functional power table 350B.

The waiting time setting unit 360B includes a first waiting time setting unit 361B, a second waiting time setting unit 362B, and a third waiting time setting unit 363B, and the determination unit 370B includes a first determination unit 371B and a second determination unit 372B. The third determination unit 373B is included. The other functional force table 340B includes a first other functional force table 341B, a second other functional force table 342B, and a third other functional force table 343B. The self-functional power table 350B includes a first self-functional power table 351B, a second self-functional power table 352B, and a third self-functional power table 353B.

Similar to the first CPU unit 100A and the second CPU unit 100B in the first embodiment, the first CPU unit 300A and the second CPU unit 300B shown in FIG. 4 have similar configurations to each other. When it is necessary to particularly distinguish the configurations provided in common by each of the first CPU unit 300A and the second CPU unit 300B, "A" is the configuration of the second CPU unit 300B in the case of the configuration of the first CPU unit 300A. In the case, "B" is added. When it is not necessary to distinguish which of the first CPU unit 300A and the second CPU unit 300B has in common, the subscripts of "A" and "B" are abbreviated.

Each functional block such as the capacity acquisition unit 310, the processing execution unit 120, the waiting time setting unit 360, and the determination unit 370 includes, for example, a CPU (central processing unit) or the like having a ROM (read only memory) or NVRAM (non-). It can be realized by reading a program stored in a storage device (storage unit 330) realized by a Volatile random access memory) or the like into a RAM (random access memory) or the like (not shown) and executing the program.

(Details of functional blocks)
The capacity acquisition unit 310 determines the performance Aby (processing capacity) of the CPU unit of the other party to be duplicated, which is related to each of the self-diagnosis process, the instruction execution process, and the I / O refresh process, which are repeatedly executed by the process execution unit 120. Acquires the indicated information (“performance information”). Specifically, the capability acquisition unit 310 displays the performance information of the other party's CPU unit related to each of the self-diagnosis process, the instruction execution process, and the I / O refresh process, and displays the self-functioning power table 350 of the other party's CPU unit. Refer to and get. The capability acquisition unit 310 uses the acquired "performance information of the other CPU unit (performance information of other machines) related to each of the self-diagnosis process, the instruction execution process, and the I / O refresh process" to other functions of the own unit. Store in the force table 340.

In particular, the capability acquisition unit 310 has the “duplication process” illustrated in FIG. 6 once before the process execution unit 120 repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. In, the performance information of other machines related to each process is acquired.

The capacity acquisition unit 310 refers to the first self-functioning power table 351 of the CPU unit of the other party to be duplicated, and "performance information indicating the performance Aby of the CPU unit of the other party to be duplicated related to the self-diagnosis process (for self-diagnosis). Other machine performance information) ”is acquired. The capacity acquisition unit 310 stores the acquired performance information of the other machine for self-diagnosis in the first other functional power table 341 of the own unit.

The capacity acquisition unit 310 refers to the second self-functioning power table 352 of the CPU unit of the other party to be duplicated, and "performance information indicating the performance Aby of the CPU unit of the other party to be duplicated related to the instruction execution process (for instruction execution). Other machine performance information) ”is acquired. The capability acquisition unit 310 stores the acquired instruction execution other machine performance information in the second other functional force table 342 of the own unit.

The capacity acquisition unit 310 refers to the third self-functioning power table 353 of the CPU unit of the other party to be duplicated, and "performance information (I) indicating the performance Aby of the CPU unit of the other party to be duplicated related to the I / O refresh process. / O Performance information of other machines for refreshing) ”is acquired. The capacity acquisition unit 310 stores the acquired performance information of the other machine for I / O refresh in the third other functional power table 343 of the own unit.

FIG. 7 is a diagram illustrating a specific example of a process of "acquiring performance information indicating the performance Aby of the CPU unit of the other party to be duplicated", which is executed once in the "duplication process". As shown in FIG. 7, the capability acquisition unit 310A provides "performance information indicating the performance Aby of the second CPU unit 300B (performance information of another machine for self-diagnosis) related to the self-diagnosis process" to the first of the second CPU unit 300B. Obtained by referring to the self-functioning power table 351B. The capacity acquisition unit 310A stores the acquired performance information of the other machine for self-diagnosis in the first other functional power table 341A of the own unit.

The capacity acquisition unit 310B refers to "performance information indicating the performance Aby of the first CPU unit 300A related to the self-diagnosis process (performance information of other machines for self-diagnosis)" with reference to the first self-functioning power table 351A of the first CPU unit 300A. And get it. The capacity acquisition unit 310B stores the acquired performance information of the other machine for self-diagnosis in the first other functional power table 341B of the own unit.

The capacity acquisition unit 310A refers to "performance information indicating the performance Aby of the second CPU unit 300B related to the instruction execution process (performance information of another machine for instruction execution)" with reference to the second self-functioning power table 352B of the second CPU unit 300B. And get it. The capability acquisition unit 310A stores the acquired instruction execution other machine performance information in the second other functional force table 342A of the own unit.

The capability acquisition unit 310B refers to "performance information indicating the performance Aby of the first CPU unit 300A related to the instruction execution process (performance information of another machine for instruction execution)" with reference to the second self-functioning power table 352A of the first CPU unit 300A. And get it. The capability acquisition unit 310B stores the acquired instruction execution other machine performance information in the second other functional force table 342B of the own unit.

The capacity acquisition unit 310A provides "performance information indicating the performance Aby of the second CPU unit 300B related to the I / O refresh process (performance information of other machines for the I / O refresh process)" to the third self-function of the second CPU unit 300B. Obtained with reference to the force table 353B. The capacity acquisition unit 310A stores the acquired performance information of the other machine for I / O refresh processing in the third other functional power table 343A of the own unit.

The capacity acquisition unit 310B provides "performance information indicating the performance Aby of the first CPU unit 300A related to the I / O refresh process (performance information of other machines for the I / O refresh process)" to the third self-function of the first CPU unit 300A. Obtained with reference to force table 353A. The capacity acquisition unit 310B stores the acquired performance information of the other machine for I / O refresh processing in the third other functional power table 343B of the own unit.

As described in the first embodiment, the process execution unit 120 repeatedly executes the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order, and when the execution of each process is completed, the "own unit" Has completed the execution of each process "is written in the common register 200.

Further, when the process execution unit 120 completes the execution of each process, the process execution unit 120 notifies the waiting time setting unit 360 and the determination unit 370 that "the own unit has completed the execution of each process". The process execution unit 120 informs the waiting time setting unit 360 that "the own unit has completed the execution of each process" and "execution time of each process (time from the start of execution to the completion of execution of each process)". You may notify. That is, the process execution unit 120 may use an internal timer to time the "execution time of each process" and notify the timed-out "execution time of each process" to the waiting time setting unit 360.

The waiting time setting unit 360 refers to the other functional power table 340 to acquire the performance information of the other machine, and refers to the self-functional power table 350 to acquire the performance information of the own machine. Further, the waiting time setting unit 360 acquires from the processing execution unit 120 that "the own unit has completed the execution of each processing". The waiting time setting unit 360 together with the fact that "the own unit has started the execution of each process" acquired from the process execution unit 120 before acquiring "the own unit has completed the execution of each process". , Calculate the execution time of each process. That is, the waiting time setting unit 360 is based on the time when "the own unit starts executing each process" timed by the internal timer and the time when "the own unit completes the execution of each process" timed by the internal timer. Calculate the execution time of each process. The execution time of each process may be timed by the process execution unit 120 using an internal timer, and may be notified from the process execution unit 120 to the waiting time setting unit 360.

The waiting time setting unit 360 calculates the "waiting time Tw" for the synchronization check processing for each processing from the acquired other machine performance information, the own machine performance information, and the execution time of each processing, and the calculated waiting time. Notify the determination unit 370 of the time Tw. Specifically, the waiting time setting unit 360 uses the performance information of other machines, the performance information of its own machine, and the execution time of each process to "wait" for the synchronization check process for each process as follows. "Time Tw" is calculated.

That is, when the "performance Aby of the other party's CPU unit to be duplicated" shown in the performance information of the other machine is higher than the "performance Abm of the own unit" shown in the performance information of the own machine, the waiting time setting unit 360 is "normally". "Waiting time Tw" is defined as "waiting time Tw". When the performance Aby of the CPU unit of the other party to be duplicated and the performance Abm of the own unit are equal, the waiting time setting unit 360 sets "normal waiting time Two" to "waiting time Tw".

The "normal waiting time Two" is a period common to the first CPU unit 300A and the second CPU unit 300B, which has a predetermined length. For example, it is set at the time of factory shipment of each unit and can be updated by the user. It is a period. The "normal waiting time Two" means that the performance Ab (particularly, the performance Ab related to each of the self-diagnosis processing, the instruction execution processing, and the I / O refresh processing) is equal between the first CPU unit 300A and the second CPU unit 300B. It is a period set on the premise of.

When the performance Aby of the CPU unit of the other party to be duplicated is lower than the performance Abm of the own unit, the waiting time setting unit 360 executes each process to the value obtained by dividing the performance Abm of the own unit by the performance Aby of the CPU unit of the other party. The period multiplied by the time is defined as "adjustment waiting time Ta". When the performance Aby of the CPU unit of the other party to be duplicated is lower than the performance Abm of the own unit, the waiting time setting unit 360 sets the "normal waiting time Two plus the adjustment waiting time Ta" (that is, "normal waiting time". "Two + adjustment waiting time Ta") "is defined as" waiting time Tw ".

<"Waiting time" for synchronization check processing related to "self-diagnosis processing"> "Waiting time Tw" for synchronization check processing related to "self-diagnosis processing" is set by the first waiting time setting unit 361. ..

The first waiting time setting unit 361 acquires the performance information of the other machine for self-diagnosis by referring to the first other functional power table 341, and obtains the performance information of the self-diagnosis machine by referring to the first self-function power table 351. get. In addition, the first waiting time setting unit 361 indicates that "the own unit has started the execution of the self-diagnosis process" and "the own unit has completed the execution of the self-diagnosis process" from the process execution unit 120. From the notification, calculate the execution time of the self-diagnosis process.

The first waiting time setting unit 361 synchronizes the self-diagnosis process from the acquired other machine performance information for self-diagnosis and the self-diagnosis own machine performance information and the calculated "execution time of the self-diagnosis process". Calculate the "waiting time Tw" for the check process.

Specifically, the first waiting time setting unit 361 has a ratio of "performance Abm of own unit related to self-diagnosis processing" and "performance Aby of the other party's CPU unit related to self-diagnosis processing". In consideration of, "adjustment waiting time Ta related to self-diagnosis processing" is calculated. Then, the first waiting time setting unit 361 adds the calculated "adjustment waiting time Ta related to the self-diagnosis processing" to the "normal waiting time Two related to the self-diagnosis processing" for the self-diagnosis processing. It is set as "waiting time Tw" for the synchronization check process of. When "Abm / Aby" is "1" or less, the first waiting time setting unit 361 sets "adjustment waiting time Ta related to self-diagnosis processing" to "0". When "Abm / Aby" is larger than "1", the first waiting time setting unit 361 sets "Adjustment waiting time Ta related to self-diagnosis processing" to "Abm" as the execution time of self-diagnosis processing of the own unit. / Aby ”multiplied value”.

The first waiting time setting unit 361 notifies the determination unit 370 of the "waiting time Tw" for the synchronization check process for the self-diagnosis process calculated by the above method.

<"Waiting time" for synchronization check processing related to "instruction execution processing"> "Waiting time Tw" for synchronization check processing related to "instruction execution processing" is set by the second waiting time setting unit 362. ..

The second waiting time setting unit 362 acquires the performance information of the other machine for instruction execution by referring to the second other functional power table 342, and obtains the performance information of the own machine for instruction execution by referring to the second self-functional power table 352. get. Further, the second waiting time setting unit 362 indicates that "the own unit has started the execution of the instruction execution process" and "the own unit has completed the execution of the instruction execution process" from the process execution unit 120. From the notification, calculate the execution time of the instruction execution process.

The second waiting time setting unit 362 synchronizes the instruction execution process from the acquired instruction execution other machine performance information and the instruction execution own machine performance information and the "execution time of the instruction execution process" obtained by calculation. Calculate the "waiting time Tw" for the check process.

Specifically, the second waiting time setting unit 362 is a ratio of "performance Abm of own unit related to instruction execution processing" and "performance Aby of the other party's CPU unit related to instruction execution processing". In consideration of, "adjustment waiting time Ta related to instruction execution processing" is calculated. Then, the second waiting time setting unit 362 adds the calculated "adjustment waiting time Ta related to the instruction execution process" to the "normal waiting time Two related to the instruction execution process" for the instruction execution process. It is set as "waiting time Tw" for the synchronization check process of. When "Abm / Aby" is "1" or less, the second waiting time setting unit 362 sets "adjustment waiting time Ta related to instruction execution processing" to "0". When "Abm / Aby" is larger than "1", the second waiting time setting unit 362 sets "Adjustment waiting time Ta related to instruction execution processing" to "Abm" as the execution time of the instruction execution processing of the own unit. / Aby ”multiplied value”.

The first waiting time setting unit 361 notifies the determination unit 370 of the "waiting time Tw" for the synchronization check processing for the instruction execution processing calculated by the above method.

<"Waiting time" for synchronization check processing related to "I / O refresh processing"> "Waiting time Tw" for synchronization check processing related to "I / O refresh processing" is the third waiting time setting unit 363. Set by.

The third waiting time setting unit 363 acquires the performance information of the other machine for I / O refresh by referring to the third other functional power table 343, and refers to the third self-functional power table 353 for the I / O refresh. Acquire machine performance information. In addition, the third waiting time setting unit 363 tells that "the own unit has started the execution of the I / O refresh process" and "the own unit has completed the execution of the I / O refresh process" from the process execution unit 120. The execution time of the I / O refresh process is calculated from the notification to that effect.

The third waiting time setting unit 363 is based on the acquired performance information of the other machine for I / O refresh and the performance information of the own machine for I / O refresh, and the calculated "execution time of the I / O refresh process". The "waiting time Tw" for the synchronization check processing for the I / O refresh processing is calculated.

Specifically, the third waiting time setting unit 363 has "performance Abm of own unit related to I / O refresh processing" and "performance Aby of the CPU unit of the other party to be duplicated related to I / O refresh processing". In consideration of the ratio with "", "Adjustment waiting time Ta related to I / O refresh processing" is calculated. Then, the third waiting time setting unit 363 adds the calculated "adjustment waiting time Ta related to the I / O refresh process" to the "normal waiting time Two related to the I / O refresh process". Set as "waiting time Tw" for synchronization check processing for I / O refresh processing. When "Abm / Aby" is "1" or less, the third waiting time setting unit 363 sets "adjustment waiting time Ta related to I / O refresh processing" to "0". When "Abm / Aby" is larger than "1", the third waiting time setting unit 363 sets "adjustment waiting time Ta related to I / O refresh processing" to "execution time of I / O refresh processing of own unit". Is multiplied by "Abm / Aby". "

The third waiting time setting unit 363 notifies the determination unit 370 of the "waiting time Tw" for the synchronization check process for the I / O refresh process calculated by the above method.

The determination unit 370 executes the synchronization check process after the waiting time Tw notified from the waiting time setting unit 360 has elapsed from the time when the own unit has completed the execution of each process. For example, the determination unit 370 refers to the common register 200 when the waiting time Tw has elapsed from the time when the own unit has completed the execution of each process, and duplicates the certain process for which the own unit has completed the execution. Check if the execution of the CPU unit of the other party is completed.

The determination unit 370 notified of "normal waiting time Two + adjustment waiting time Ta" as the waiting time Tw executes the waiting process from the time when "the own unit completes the execution of each process" until the adjustment waiting time Ta occurs. .. Then, the determination unit 370 executes the synchronization check process after the execution of the standby process is completed (that is, after the adjustment waiting time Ta has elapsed from the time when the own unit has completed the execution of each process). That is, after the execution of the standby process is completed, the determination unit 370 can confirm that the CPU unit of the other party has completed the execution of the process whose execution has been completed by the own unit by the time the normal waiting time Two elapses. Is it judged? In other words, the determination unit 370 determines whether the processing completed by the own unit can be confirmed to be completed by the CPU unit of the other party from the time when the execution of the standby processing is completed until the normal waiting time Two elapses.

The determination unit 370 notified of the "normal waiting time Two" as the waiting time Tw immediately executes the synchronization check process when "the own unit completes the execution of each process". That is, the determination unit 370 determines "whether it is possible to confirm that the CPU unit of the other party has completed the execution of the process whose execution has been completed by the own unit by the time the normal waiting time Two elapses". In other words, the determination unit 370 determines whether the processing completed by the own unit can be confirmed by the CPU unit of the other party from the time when the execution of the own unit is completed until the normal waiting time Two elapses.

<Synchronous check process related to "self-diagnosis process"> The first determination unit 371 executes the synchronous check process related to "self-diagnosis process". That is, the first determination unit 371 reaches the time when the "waiting time Tw" for the self-diagnosis process notified from the first waiting time setting unit 361 elapses from the time when the execution of the self-diagnosis process of the own unit is completed. , Check "whether the other party's CPU unit has completed the execution of the self-diagnosis process". If it cannot be confirmed that "the other party's CPU unit has completed the execution of the self-diagnosis process" by the time "the" waiting time Tw "for the self-diagnosis process" elapses, the first determination unit 371 will perform the other party's CPU. Judge that an error has occurred in the unit.

<Synchronous check process related to "instruction execution process"> The second determination unit 372 executes the synchronous check process related to "instruction execution process". That is, the second determination unit 372 has elapsed from the time when the execution of the instruction execution process of the own unit is completed until the "waiting time Tw" for the instruction execution process notified from the second waiting time setting unit 362 elapses. , Check "whether the other party's CPU unit has completed the execution of the instruction execution process". If it cannot be confirmed that "the other party's CPU unit has completed the execution of the instruction execution process" by the time "the" waiting time Tw "for the instruction execution process" elapses, the second determination unit 372 determines that the other party's CPU has completed the execution. Judge that an error has occurred in the unit.

<Synchronous check process related to "I / O refresh process"> The third determination unit 373 executes the synchronous check process related to "I / O refresh process". That is, the third determination unit 373 receives the "waiting time Tw" for the I / O refresh process notified from the third waiting time setting unit 363 from the time when the execution of the I / O refresh process of the own unit is completed. By the time it has elapsed, it is confirmed whether the CPU unit of the other party has completed the execution of the I / O refresh process. If it cannot be confirmed that "the CPU unit of the other party has completed the execution of the instruction execution process" by the time "the" waiting time Tw "for the I / O refresh process" elapses, the third determination unit 373 determines that the other party has completed the execution. It is determined that an abnormality has occurred in the CPU unit of.

The determination unit 370A refers to the second register 220 of the common register 200, and indicates whether or not there is a writing indicating that "execution by the process execution unit 120B has been completed" for a certain process for which the process execution unit 120A has completed execution. confirm. If the determination unit 370A does not write in the second register 220 that "execution by the process execution unit 120B has been completed" for a certain process for which the process execution unit 120A has completed execution, an error occurs in the second CPU unit 300B. Judge that it has occurred.

The determination unit 370B refers to the first register 210 of the common register 200, and indicates whether or not there is a writing indicating that "execution by the process execution unit 120A has been completed" for a certain process for which the process execution unit 120B has completed execution. confirm. If the determination unit 370B does not write in the first register 210 that "execution by the process execution unit 120A has been completed" for a certain process for which the process execution unit 120B has completed execution, an error occurs in the first CPU unit 300A. Judge that it has occurred.

(Details of memory)
The storage unit 330 is a storage device that stores various data used by each of the first CPU unit 300A and the second CPU unit 300B. In the storage unit 330, each of (1) a control program, (2) an OS program, and (3) a first CPU unit 300A and a second CPU unit 300B executed by each of the first CPU unit 300A and the second CPU unit 300B is executed. The application program for executing the various functions possessed by the application program and (4) various data to be read when the application program is executed may be stored non-temporarily. The data of (1) to (4) above may be, for example, ROM (read only memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (registered trademark) (Electrically EPROM), HDD (Hard Disc Drive), or the like. Stored in a non-volatile storage device. Each of the first CPU unit 300A and the second CPU unit 300B may include a temporary storage unit (not shown). The temporary storage unit is a so-called working memory that temporarily stores data used for calculation, calculation results, etc. in the process of various processes executed by each of the first CPU unit 300A and the second CPU unit 300B, and is a RAM (Random). It consists of volatile storage devices such as Access Memory). Which data is stored in which storage device is appropriately determined from the purpose of use, convenience, cost, physical restrictions, etc. of each of the first CPU unit 300A and the second CPU unit 300B. The storage unit 330 further stores the other functional power table 340 and the self-functional power table 350.

In the other functional power table 340, the performance information of the other machine, which is the information indicating the performance Aby (processing capacity) of the CPU unit of the other party to be duplicated, is stored. As described with reference to FIG. 3, the capability acquisition unit 310 transfers the performance information of the other machine acquired by referring to the self-functional power table 350 of the other party's CPU unit to be duplicated in the other functional power table 340 of the own unit. Store.

In the first other functional power table 341, "performance indicating the performance Aby of the CPU unit of the other party to be duplicated related to the self-diagnosis process" stored in the first self-functional power table 351 of the CPU unit of the other party to be duplicated. "Information" is stored by the ability acquisition unit 310.

In the second other functional power table 342, "performance indicating the performance Aby of the CPU unit of the other party to be duplicated related to the instruction execution process" stored in the second self-functional power table 352 of the CPU unit of the other party to be duplicated. "Information" is stored by the ability acquisition unit 310.

In the third other functional power table 343, the performance Aby of the CPU unit of the other party to be duplicated, which is stored in the third self-functional power table 353 of the CPU unit of the other party to be duplicated, is displayed. "Performance information to be shown" is stored by the ability acquisition unit 310.

The self-functional power table 350 stores self-machine performance information, which is information indicating the performance Abm (processing capacity) of the self-unit. For example, "how much performance the self-unit has as compared with the reference CPU unit (? Does it have processing capacity)? ”Is stored in the performance information of the own machine. The own machine performance information is stored in the self-functional power table 350 at the time of shipment from each of the first CPU unit 300A and the second CPU unit 300B, for example.

In the first self-functional power table 351, "performance information indicating the performance Abm of the own unit related to the self-diagnosis process (particularly, the performance Abm of the reference CPU unit related to the self-diagnosis process" is relative to the performance Abm. ) ”Is stored.

In the second self-functional power table 352, "performance information indicating the performance Abm of the own unit related to the instruction execution process (particularly, the performance Abm of the reference CPU unit related to the instruction execution process" is shown. ) ”Is stored.

In the third self-functional power table 353, "performance information indicating the performance Abm of the own unit related to the I / O refresh process (particularly, the performance Abb of the reference CPU unit related to the I / O refresh process" is relative to. Performance Abm) ”is stored.

(Arrangement of CPU units)
In order to facilitate understanding of each of the first CPU unit 300A and the second CPU unit 300B whose configurations have been described with reference to FIGS. 4 and the like, they are arranged as follows. That is, each of the first CPU unit 300A and the second CPU unit 300B is a CPU unit to be duplicated in the PLC 20 (controller) like each of the first CPU unit 100A and the second CPU unit 100B. Each of the first CPU unit 300A and the second CPU unit 300B includes a waiting time setting unit 360 (setting unit) and a determination unit 370. The waiting time setting unit 360 sets the waiting time Tw in consideration of the ratio between the performance Abm (processing capacity) of the own unit and the performance Aby of the CPU unit of the other party to be duplicated. If the determination unit 370 cannot confirm the completion of the execution of the processing of the other CPU unit from the time when the execution of the processing in the own unit is completed to the time when the waiting time Tw set by the waiting time setting unit 360 elapses, the other party's CPU unit It is determined that an abnormality has occurred in the CPU unit.

Therefore, each of the first CPU unit 300A and the second CPU unit 300B, like each of the first CPU unit 100A and the second CPU unit 100B, appropriately waits in consideration of the difference in performance Ab between the own unit and the other CPU unit. Time Tw can be set. That is, each of the first CPU unit 300A and the second CPU unit 300B performs the synchronization check process without providing an unnecessary waiting time Tw in consideration of the difference in performance Ab between the CPU unit of the other party to be duplicated and the own unit. It can be done accurately.

In each of the first CPU unit 300A and the second CPU unit 300B, the process (process to be the target of the synchronization check process) includes a self-diagnosis process, an instruction execution process, and an I / O refresh process. The waiting time setting unit 360 (specifically, each of the first waiting time setting unit 361, the second waiting time setting unit 362, and the third waiting time setting unit 363) has self-diagnosis processing, instruction execution processing, and , Wait time Tw is set for each of the I / O refresh processes. The determination unit 370 (specifically, each of the first determination unit 371, the second determination unit 372, and the third determination unit 373) has a self-diagnosis process, an instruction execution process, and an I / O refresh process. That is, the synchronization check process is executed.

Each of the first CPU unit 300A and the second CPU unit 300B determines the synchronization between the own unit and the other CPU unit at the timing of completion of each execution of the self-diagnosis process, the instruction execution process, and the I / O refresh process. be able to.

Each of the first CPU unit 300A and the second CPU unit 300B executes the duplication process once before repeatedly executing the self-diagnosis process, the instruction execution process, and the I / O refresh process in this order. Each of the first CPU unit 300A and the second CPU unit 300B acquires the performance Aby of the other CPU unit from the other CPU unit in the duplication process.

Each of the first CPU unit 300A and the second CPU unit 300B takes into consideration the performance Aby of the other CPU unit acquired before repeatedly executing each of the processes, and waits for the determination of each process. It has the effect of being able to set Tw.

In each of the first CPU unit 300A and the second CPU unit 300B, the waiting time setting unit 360 sets each waiting time Tw of the self-diagnosis process, the instruction execution process, and the I / O refresh process as follows. That is, the waiting time setting unit 360 considers the ratio between the performance Abm of the own unit and the performance Aby of the CPU unit of the other party related to the execution of each of the self-diagnosis process, the instruction execution process, and the I / O refresh process. Then, the waiting time Tw of each process is set. Specifically, the first waiting time setting unit 361 considers the ratio between the performance Abm of the own unit and the performance Aby of the CPU unit of the other party related to the self-diagnosis process, and synchronizes the self-diagnosis process with the synchronization check process. The waiting time Tw for is set. The second waiting time setting unit 362 considers the ratio between the performance Abm of the own unit and the performance Aby of the CPU unit of the other party related to the instruction execution processing, and waits for the synchronization check processing for the instruction execution processing. Tw is set. The third waiting time setting unit 363 considers the ratio between the performance Abm of the own unit and the performance Aby of the CPU unit of the other party related to the I / O refresh process, and performs the synchronization check process for the I / O refresh process. The waiting time Tw for this is set.

Each of the first CPU unit 300A and the second CPU unit 300B considers the difference in performance Ab between the own unit and the other CPU unit related to each of the self-diagnosis processing, the instruction execution processing, and the I / O refresh processing. , Set the waiting time Tw for each process.

Therefore, each of the first CPU unit 100A and the second CPU unit 100B can set the waiting time Tw of each process according to the performance Ab of the own unit and the other CPU unit related to each process. Play.

(motion)
FIG. 6 is a diagram illustrating an outline of processing executed by each of the first CPU unit 300A and the second CPU unit 300B. The processing executed by each of the first CPU unit 300A and the second CPU unit 300B shown in FIG. 6 is different from the processing executed by each of the first CPU unit 100A and the second CPU unit 100B shown in FIG. 2 in the following points. ..

That is, each of the first CPU unit 300A and the second CPU unit 300B grasps the performance Ab of the own unit and the other CPU unit for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process that are repeatedly executed. .. Then, each of the first CPU unit 300A and the second CPU unit 300B sets the "waiting time Tw" at the time of the synchronization check processing for each processing by using the performance Ab of the own unit and the other CPU unit related to each processing. do. Each of the first CPU unit 300A and the second CPU unit 300B "completes the execution of each process by the other CPU unit" from the time when the execution of each process by the own unit is completed until the "waiting time Tw" for each process elapses. Is determined.

In other respects, the "process executed by each of the first CPU unit 300A and the second CPU unit 300B" is the same as the "process executed by each of the first CPU unit 100A and the second CPU unit 100B".

That is, the "process executed by each of the first CPU unit 300A and the second CPU unit 300B" is a control method of the CPU unit duplicated in the PLC 20 (controller), and includes a setting step and a determination step. In the setting step, the waiting time Tw is set in consideration of the ratio between the performance Abm of the own unit and the performance Aby of the CPU unit of the other party to be duplicated. In the determination step, if it is not possible to confirm the completion of execution of the process in the CPU unit of the other party from the time when the execution of the process in the own unit is completed until the waiting time Tw set in the setting step elapses, the CPU unit of the other party is informed. Judge that an abnormality has occurred.

Therefore, in the "process executed by each of the first CPU unit 300A and the second CPU unit 300B", even if the performance Ab does not match between the own unit and the other CPU unit, the own unit and the other CPU unit It has the effect of being able to set an appropriate waiting time Tw in consideration of the difference in performance Ab. That is, in the "process executed by each of the first CPU unit 300A and the second CPU unit 300B", an unnecessary waiting time Tw is not provided in consideration of the difference in performance Ab between the CPU unit of the other party to be duplicated and the own unit. In addition, it has the effect that the synchronization check process can be performed accurately.

§4. Modification Example Up to now, an example has been described in which the first CPU unit 100A and the second CPU unit 100B (or the first CPU unit 300A and the second CPU unit 300B) perform synchronization check processing using the common register 200. .. However, the method of using the common register 200 is only an example of a method of realizing the synchronization check process. The synchronization check process is, for example, a method in which the first CPU unit 100A and the second CPU unit 100B (or the first CPU unit 300A and the second CPU unit 300B) check synchronization while communicating with each other at their serial ports. It may be realized. The first CPU unit 100A and the second CPU unit 100B (or the first CPU unit 300A and the second CPU unit 300B) confirm that the processing of the other CPU unit has been executed while communicating with each other through their serial ports. You may.

Further, an example in which the self-diagnosis process, the instruction execution process, and the I / O refresh process are repeatedly executed in this order, and the synchronization check process related to each of these processes is executed after the execution of each of these processes is completed. I've explained. However, in addition to the self-diagnosis process, the instruction execution process, and the I / O refresh process, even if another process is repeatedly executed in the same manner as the self-diagnosis process, the instruction execution process, and the I / O refresh process. good. In that case, the synchronization check process will be executed after the execution is completed for this other process as well.

For example, in addition to the self-diagnosis process, the instruction execution process, and the I / O refresh process, the signal is transmitted / received to / from a communication network different from the communication network in which the signal is transmitted / received in the I / O refresh process. "Other communication processing" may be executed repeatedly. That is, the self-diagnosis process, the instruction execution process, the I / O refresh process, and other communication processes are repeatedly executed in this order, and after the execution of each of these processes is completed, the synchronization check process related to each of these processes is executed. May be done.

[Example of implementation by software]
Control blocks of each of the first CPU unit 100A, the second CPU unit 100B, the first CPU unit 300A, and the second CPU unit 300B (in particular, the capacity acquisition unit 110, the processing execution unit 120, the waiting time setting unit 160, the determination unit 170, and the capacity). The acquisition unit 310, the waiting time setting unit 360, and the determination unit 370) may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or a CPU (CenTral Processing Unit) may be realized. It may be realized by software using it.

In the latter case, each of the first CPU unit 100A, the second CPU unit 100B, the first CPU unit 300A, and the second CPU unit 300B is a CPU that executes an instruction of a program that is software that realizes each function, the above program, and various data. Is equipped with a ROM (Read Only Memory) or a storage device (these are referred to as "recording media") readable by a computer (or CPU), a RAM (Random Access Memory) for expanding the above program, and the like. Then, the object of the present invention is achieved by the computer (or CPU) reading the program from the recording medium and executing the program. As the recording medium, a "non-temporary tangible medium", for example, a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, the program may be supplied to the computer via any transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. The present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the above program is embodied by electronic transmission.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

10 PLC
20 PLC
100A 1st CPU unit (CPU unit)
100B 2nd CPU unit (CPU unit)
300A 1st CPU unit (CPU unit)
300B 2nd CPU unit (CPU unit)
160 hours setting unit (setting unit)
360 time setting unit (setting unit)
170 Judgment unit 370 Judgment unit Ab Performance (processing capacity)
Tw waiting time

Claims (6)

It is a CPU unit that is duplicated in the controller.
A setting unit that sets the waiting time in consideration of the ratio between the processing capacity of the own unit and the processing capacity of the CPU unit of the other party to be duplicated.
If it is not possible to confirm the completion of execution of the process in the CPU unit of the other party from the time when the execution of the process in the own unit is completed until the waiting time set by the setting unit elapses, an abnormality occurs in the CPU unit of the other party. Judgment unit that determines that it has occurred,
Equipped with
The processing includes self-diagnosis processing for diagnosing whether or not there is an abnormality in the hardware of the own unit, instruction execution processing for generating a signal for controlling an external device other than the CPU unit of the other party, and CPU unit of the other party. Includes I / O refresh processing to exchange data with external devices
The setting unit sets the waiting time for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process.
The determination unit is a CPU unit that executes the determination for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process . Before the self-diagnosis process, the instruction execution process, and the I / O refresh process are repeatedly executed in this order, a duplication process of acquiring the processing capacity of the CPU unit of the other party from the CPU unit of the other party is performed. The CPU unit according to claim 1 , which is executed once. The setting unit sets the waiting time for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process to the self-diagnosis process, the instruction execution process, and the I / O refresh process. The CPU unit according to claim 1 or 2 , which is set in consideration of the ratio between the processing capacity of the own unit and the processing capacity of the other CPU unit related to each execution. It is a control method of the CPU unit that is duplicated in the controller.
A setting step to set the waiting time in consideration of the ratio between the processing capacity of the own unit and the processing capacity of the CPU unit of the other party to be duplicated,
If it is not possible to confirm the completion of execution of the process in the CPU unit of the other party from the time when the execution of the process in the own unit is completed until the waiting time set in the setting step elapses, the CPU unit of the other party is abnormal. Judgment step to determine that has occurred, and
Including
The processing includes self-diagnosis processing for diagnosing whether or not there is an abnormality in the hardware of the own unit, instruction execution processing for generating a signal for controlling an external device other than the CPU unit of the other party, and CPU unit of the other party. Includes I / O refresh processing to exchange data with external devices
The setting step sets the waiting time for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process.
The determination step is a control method for executing the determination for each of the self-diagnosis process, the instruction execution process, and the I / O refresh process . An information processing program for operating a computer as a CPU unit according to any one of claims 1 to 3 , and an information processing program for operating a computer as each part. A computer-readable recording medium on which the information processing program according to claim 5 is recorded.

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