JP5012548B2 - Programmable controller - Google Patents

Description

  The present invention relates to a programmable controller that refers to a parameter and performs a predetermined operation in accordance with the parameter.

As is conventionally known, a programmable controller (hereinafter also abbreviated as PLC) is used as a control device for factory automation (FA). This PLC is generally composed of a plurality of modules. These modules include a CPU module for controlling the overall control of the PLC, an input module for inputting signals from switches and sensors installed at appropriate positions in FA production equipment and facility equipment, and control signals to actuators. There are an output module for outputting, a communication module for connecting to a communication network, and a power supply module for supplying operating power to each of these modules. The PLC is configured by appropriately combining these modules.
The CPU module fetches a signal input from the input module into an I / O (Input / Output) memory of the CPU module (input refresh), and performs a logical operation based on a user program (sequence program) registered in advance (calculation execution). The operation execution result is written in the I / O memory, sent to the output module (output refresh), and then a series of processes for performing so-called peripheral system processing (loader processing, various system processing) is repeated. The CPU module controls a target device (hereinafter referred to as a control target device) by repeating these processes.

On the other hand, there are various types of interface specifications for such control target devices. Since it is inefficient to replace the input / output module according to the interface specification of the control target device, the PLC generally sets a parameter for determining the operation mode according to the interface specification of the control target device in the PLC. For this reason, the operation is set according to the parameters. This parameter is stored in advance in a nonvolatile memory built in the PLC, and the handling of signals between the control target device and the input / output module and the handling of signals between the CPU module and the input / output module are determined. Read when the PLC is powered on. In this way, the PLC can respond to various applications (user requests) with a single piece of hardware.
The above-described parameters are used by being updated as appropriate according to user specifications. In order to update this parameter, a setting device such as a programming loader is connected to the PLC, and the parameter and flag information for prompting the parameter to be updated are downloaded to the PLC. The PLC performs parameter updating by periodically checking the flag information.
Incidentally, in order to rewrite the parameters of the nonvolatile memory so as to change the currently set parameters, the following procedure is generally performed. That is, (1) First, the PLC is stopped, and the operation mode of the PLC is changed to the parameter update mode by a jumper pin, a dip switch or the like. (2) Next, parameter download is executed. Thereby, the parameter is held in the nonvolatile memory. (3) When downloading is completed, the PLC is changed to the program execution mode and then restarted.

There has been proposed a PLC that saves the trouble of downloading and restarting parameters after stopping the PLC. (For example, see Patent Document 1). This PLC includes a first memory that holds a program for rewriting a program held during program operation, a second memory that backs up the program held in the first memory, and when executing the program. And a third memory for use. Then, the PLC holds the program downloaded during operation in the second memory, confirms whether or not the download has been performed normally, copies the downloaded program to the first memory, and then expands the program to the third memory. It is configured.
JP 2004-272629 A

The conventional PLC determines whether or not the parameter has changed during the operation of the PLC when the update process is executed depending on whether or not flag information that prompts the update of the parameter held in the nonvolatile memory is set. I can't. Of course, even if the parameter for update is the same as the currently held parameter, the update process must be executed each time the flag is set (although the parameter update process is unnecessary). did not become. For this reason, this type of PLC has a problem that the rewrite frequency of the non-volatile memory is high and its life is greatly shortened.
On the other hand, a method of comparing a currently held parameter with the parameter itself for update and detecting a change in the parameter is also conceivable (to avoid unnecessary parameter update as described above). However, such a method has a problem that the comparison time increases in accordance with the amount of parameters.
Further, if a parameter stored in advance in the nonvolatile memory is damaged, an incorrect operation mode is entered at the time of startup, which causes a malfunction of the PLC. This is often noticed abnormally only after the PLC is actually operated, and may cause an accident. And it was undeniable that investigating the cause would require a lot of time only by the abnormal behavior.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a PLC having a long life that can reflect parameter updates while the PLC is operating. .
Furthermore, the present invention provides a highly reliable PLC that accurately notifies the damaged parameter (without input / output refresh and calculation) without operating the PLC when a damaged parameter is detected. is there. It is a further object of the present invention to save time for repairing damaged parameters by the user.

In order to achieve the above-described object, a programmable controller according to claim 1 of the present invention is a programmable controller that operates by reading a parameter for determining an operation mode and setting an operation mode according to the parameter. First storage means in which a first check code for verifying the validity of the parameter is held in advance, and first transfer for transferring the parameter held in the first storage means to the second storage means When the flag indicating that the parameter held in the second storage means is updated is set, the validity of the parameter is verified from the parameter updated in the second storage means. Check code calculating means for calculating a second check code for the first check code and the second check code Check code comparing means for comparing the check code, and when the check code comparing means determines that the first check code and the second check code are different, the parameter stored in the second storage means is updated. A second transfer means for transferring the parameter and the second check code, respectively, to the first storage means and overwriting the parameter and the first check code previously held in the first storage means; Parameter setting means for reading a parameter overwritten by a parameter previously stored in the storage means and resetting the operation mode.
A programmable controller according to claim 2 is a programmable controller that operates by reading a parameter for determining an operation mode, setting an operation mode according to the parameter, and verifying the validity of the parameter and the parameter. First storage means in which one check code is held in advance, first transfer means for transferring the parameters and first check code held in the first storage means to the second storage means, When a flag indicating that the parameter held in the second storage means has been updated is set, the second parameter for verifying the validity of the parameter from the parameter updated in the parameter held in the second storage means A check code calculating means for calculating a second check code, and a first code stored in the second storage means Check code comparing means for comparing the check code and the second check code, and the first check code and the second check code held in the second storage means by the check code comparing means are determined to be different When the parameter stored in the second storage means is updated, the second check code is transferred to the first storage means, respectively, and the parameter stored in advance in the first storage means and the second check code are transferred. A second transfer means for overwriting one check code; a parameter setting means for reading a parameter overwritten by a parameter stored in advance in the first storage means and resetting the operation mode;
It is characterized by providing.

A programmable controller according to a third aspect is the programmable controller according to any one of the first to second aspects, wherein the parameter and the first check code are a plurality of predetermined devices connected to the programmable controller in advance. The check code calculation means calculates a check code for verifying the validity of each parameter for each classified and held parameter when the programmable controller is initially activated. The check code comparison means compares the plurality of calculated check codes with the first check code corresponding to the check code, and the programmable controller further determines that the check codes match with the check code comparison means. When Characterized in that to set the parameters to the chromatography data setting means.
A programmable controller according to a fourth aspect is the programmable controller according to any one of the first to second aspects, wherein the parameter and the first check code include a plurality of parameters in advance for each predetermined device connected to the programmable controller. The check code calculation means calculates a check code for verifying the validity of each parameter for each classified and held parameter when the programmable controller is initially activated. The check code comparing means compares the plurality of calculated check codes with the first check code corresponding to the check code, and the programmable controller further determines that the check code is different by the check code comparing means. Difference Characterized in that it comprises a notifying means for notifying a group that contains a check code.

The programmable controller according to claim 5 is characterized in that the first or second check code is a SUM value obtained by sequentially adding parameters, or a value obtained by cyclically calculating the parameters.
The programmable controller according to claim 6 is characterized in that the first storage means is a rewritable nonvolatile memory.

According to the configuration of the first aspect of the present invention, the parameter and the first check code for verifying the validity of the parameter are held in the first storage unit in advance, and the validity of the parameter is verified. When the check code is calculated at a predetermined cycle, and the calculated check code and the first check code are compared and different, the operation mode is set so that the PLC is in an operating state (in operation) The parameters can be updated and reflected as they are. That is, the PLC according to claim 1 of the present invention can change the operation mode while the PLC is operating.
According to the second aspect of the present invention, the parameter and the first check code for verifying the validity of the parameter are held in the first storage unit in advance, and the first storage unit The parameter is transferred to the second storage means having a faster access time, and a check code for verifying the validity of the parameter held by the second storage means is calculated at a predetermined cycle. When the calculated check code and the first check code are compared and different, the parameters held in the second storage means and the check code calculated from the parameters are respectively transferred to the first storage means, Since the operation mode is set according to the transferred parameter, the parameter can be updated and reflected while the PLC is in an operating state (in operation). Furthermore, since unnecessary updating of parameters can be prevented, it is possible to change the operation mode while the PLC is operating, and to provide a PLC having a long life.

According to the third aspect of the present invention, the parameter and the first check code for verifying the validity of the parameter are held in the first storage unit in advance, and the first storage unit The parameter and the first check code are transferred to the second storage means having a faster access time, and a check code for verifying the validity of the parameter held by the second storage means is calculated at a predetermined cycle. When the calculated check code is different from the check code held by the second storage means, the parameter stored in the second storage means and the check code calculated from the parameter are stored in the first storage means. Since the operation mode is set according to the transferred parameters, the parameters can be updated and reflected at high speed while the PLC is in the operating state (in operation). Furthermore, since unnecessary updating of parameters can be prevented, it is possible to change the operation mode while the PLC is operating, and to provide a PLC having a long life.
According to the configuration of claim 4 of the present invention, the parameter and the first check code are classified into a plurality of groups in advance for each predetermined device connected to the programmable controller and held in the first storage means. Is done. Then, at the initial startup of the programmable controller, a check code for verifying the validity of each parameter is calculated for each parameter that is classified and held, and the check code corresponds to the calculated check code and the check code. The first check code is compared with each other, and when they all match, the parameter is set, so the PLC does not operate in the wrong operation mode, prevents the PLC from malfunctioning, and prevents accidents. It is possible to provide a PLC with high reliability that can be used. That is, it is possible to provide a highly reliable PLC that is always driven in the correct operation mode.

According to the fifth aspect of the present invention, the parameter and the first check code are classified into a plurality of groups in advance for each predetermined device connected to the programmable controller and held in the first storage unit. Is done. Then, at the initial startup of the programmable controller, a check code for verifying the validity of each parameter is calculated for each parameter that is classified and held, and the check code corresponds to the calculated check code and the check code. The first check code is compared with each other, and when one of them is different, the group including the different check code is notified, so that the user can easily know the group of the damaged parameter. For this reason, in the repair operation of the damaged parameter, it is only necessary to repair the parameter of the group including the specific damaged parameter, so that the repair time can be saved.
According to the configuration of the sixth aspect of the present invention, since the SUM value that is generally well known is used as the check code, the check code calculating means can be implemented with a simple addition program (a program that does not require special calculation). Can be created.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings of FIGS. These drawings are for explaining an embodiment of the present invention, and the present invention is not limited by these drawings.

FIG. 1 is an internal configuration diagram of a programmable controller according to Embodiment 1 of the present invention. In FIG. 1, 100 is a programmable controller (hereinafter referred to as PLC) of the present invention, 105 is an input unit to which a signal from a sensor (not shown), etc. is given, 107 is a display unit for displaying measurement results, 108 is various setting operations, An operation unit 104 is a communication unit for the PLC 100 to communicate with another device (not shown) via the network 110.
Reference numeral 102 denotes a non-volatile memory (first storage means) such as an E ² PROM or flash memory that holds parameters for determining the operation mode of the PLC, and 103 denotes a working memory (second storage means) such as an SRAM. Reference numeral 106 denotes an output unit that gives a control signal to an external device such as an actuator (not shown). Part.
The control unit 101 adds the parameters in order, and adds a check code calculation unit 101a to obtain a total value (SUM value), and a check for comparing the SUM value previously stored in the nonvolatile memory with the SUM value calculated from the parameter Refers to the code comparison means 101b and the parameters held in the nonvolatile memory, determines the operation mode of the control unit 101 itself according to the value, and determines the operation of the circuit for the input unit 105 and the output unit 106 Parameter setting means 101c for providing a predetermined signal.

The check code calculation unit 101a, the check code comparison unit 101b, and the parameter setting unit 101c are all programs held in an internal memory (not shown) of the control unit 101.
Reference numeral 109 denotes an internal bus that connects the control unit 101 to the nonvolatile memory 102, the work memory 103, and the communication unit 104.
In addition, the PLC according to the first embodiment of the present invention can be realized by configuring each component such as the control unit 101, the input unit 105, and the output unit 106 in a module configuration.
Schematically, the PLC 100 according to the first embodiment of the present invention configured as described above is characterized in that a parameter for determining an operation mode of the PLC held in advance in a nonvolatile memory (first storage means). When (original parameter) is updated, this update is detected, and even if the PLC is operating, the operation mode is reset and reflected.
The operation of the PLC according to the first embodiment of the present invention having such characteristics will be described in more detail.
The PLC 100 according to the first embodiment of the present invention is configured such that the control unit 101 refers to a parameter stored in advance in the nonvolatile memory 102 and sets an operation according to this parameter at the initial startup after power-on. ing. And it can respond to various user applications by changing the above-mentioned parameter suitably.

FIG. 2 is a diagram illustrating memory information related to parameters held in the nonvolatile memory 102 of the PLC 100 according to the first embodiment of the present invention. In this figure, reference numeral 200 denotes a parameter area assigned to a predetermined address of the nonvolatile memory. 201 is an input parameter that determines how to handle the signal between the control unit 101 and the input unit 105 and the operation of the circuit for the input unit 105, and 202 is a check code based on the input parameter 201. This is the input parameter SUM value obtained by the calculation means 101a. 203 is an output parameter that determines how the signal is handled between the control unit 101 and the output unit 106 and the operation of the output unit 106, and 204 is obtained by the check code calculation unit 101 a based on the output parameter 203. Output parameter SUM value.
The SUM value (check code) handled in the present invention is a check code that is widely known as a code for checking the validity of data, and is obtained by sequentially adding a plurality of parameters. is there.
FIG. 3 is a table showing examples of parameters classified in advance into a plurality of groups for each predetermined device (module) connected to the programmable controller. The parameter classification shown in FIG. 3 means a group for each predetermined device (module), and No. 1 to No. 5 are items classified into the input parameters 201 shown in FIG. NO. 10 is an item classified as the output parameter 203 shown in FIG. Further, No. 11 is an item that is not shown in FIG. 2 but is classified as an input / output parameter.

In FIG. 3, parameters classified as input parameters will be described. For example, the No. 1 operation range setting parameter is a parameter for setting an operation range for an analog input device (module), and the A / D conversion characteristics can be changed by setting this parameter. The conversion permission / prohibition setting parameter of No. 2 is a parameter for determining whether or not to perform A / D conversion for the analog input device (module). The disconnection scale setting parameter of NO.3 is whether the A / D conversion value of the analog input device (module) is the upper limit value when the external load connected to the analog input device (module) is not connected. , A parameter for determining whether to set the lower limit value. The No. 4 average value count setting parameter is a parameter that determines the number of acquisitions for calculating the average value of A / D conversion values for analog input devices (modules), such as moving average, simple average, and weighted average. Used for various purposes.
Similarly, in FIG. 3, parameters classified as output parameters will be described. For example, the output permission / prohibition parameter of No. 6 is a parameter that determines whether or not to perform D / A conversion on an analog output device (module). The alarm use / non-use setting parameter of No. 7 is a parameter for setting whether or not to issue an alarm when the A / D conversion value of the analog input device (module) reaches a threshold for issuing an alarm described later. The alarm type parameter No. 8 is a parameter for setting an alarm type (such as an upper limit / lower limit absolute value alarm or an upper limit / lower limit deviation alarm) when an alarm is issued. The ALM set value parameter of No. 9 is a parameter that receives the A / D conversion value of the analog input module and determines a threshold value for issuing an alarm. The NO.10 alarm ON delay time parameter is a parameter that sets the time from when the A / D conversion value of the analog input device (module) reaches the threshold value for issuing an alarm until the alarm is issued. It is.

In FIG. 3, parameters classified as input / output parameters will be described. The scaling setting parameter of No. 12 is a parameter that determines the output signal characteristic of the analog output device (module) with respect to the input signal to the analog input device (module). By setting this parameter, the A / D conversion value and D / A conversion value of the analog input / output device (module) can be changed to a scale (amount) converted to an industrial value.
As described above, the parameters that determine the operation mode of the programmable controller are classified into a plurality of groups for each predetermined device (module) connected to the programmable controller and are held in the nonvolatile memory 102.
FIG. 4 is a flowchart for explaining the operation of the programmable controller according to the first embodiment of the present invention. The present invention will be described in detail with reference to FIG. Here, after the power is turned on, the state for initializing the PLC is the initial startup phase (S301 to S304), the normal operation state after the initialization is the operation phase (S305 and later), and the abnormal state that stops the PLC is It is defined as an abnormal phase (S320). The check code calculation means 101a for calculating the SUM value described in the present embodiment is a program executed by the control unit 101 that adds the parameters in order and makes the total value.

In S301, the control unit 101 calculates the SUM values of the input parameters 201 and the output parameters 203 classified and held for each group, and transfers them to a save area (not shown) in the control unit 101.
Next, the control unit 101 proceeds to S302, and compares the SUM value and input parameter SUM value 202 for the input parameter 201 calculated in S301, and the SUM value and output parameter SUM value 204 for the output parameter 203 calculated in S301, respectively. To do. When the SUM values compared to these pairs are equal, the control unit 101 determines that the parameters are normal, and proceeds to S304. If any one of the SUM values compared to these pairs is different, there is a high possibility that the parameter is abnormal or the nonvolatile memory is abnormal. Therefore, since it is assumed that the PLC does not operate normally when the PLC is operated as it is, the control unit 101 determines that the parameter is abnormal and shifts to S320 (abnormal phase) without operating the PLC. .
The control unit 101 that has proceeded to S320 notifies (displays) the group name including the parameter that is abnormal to the display unit 107, and the abnormality (to the other device connected to the apparatus via the network 110) Notify that the parameter is abnormal and the name of the group containing the abnormal parameter).

If it is determined in S302 that the parameters are normal, the control unit 101 proceeds to S304 and refers to the input parameters 201 and the output parameters 203. In accordance with the value, the control unit 101 determines its own operation mode, and gives a predetermined signal for determining the operation of the circuit to the input unit 105 and the output unit 106. That is, the control unit 101 determines whether or not the input parameter 201 and the output parameter 203 are normal in the initial startup phase, and sets the parameters only when each parameter is normal, and the operation phase (S305 and later). Migrate to
The processing of the control unit 101 proceeds to S305, and the signal input from the input unit 105 is taken into an I / O memory (not shown) in the control unit 101 (input processing). In step S306, the control unit 101 performs a logical operation based on a program stored in advance. Next, in step S307, the control unit 101 writes the calculation execution result in the I / O memory and sends it to the output unit 106 (output processing). After this output processing, the control unit 101 confirms whether or not the data of the input parameter 201 and the output parameter 203 has been updated in S308 using a data update completion flag (not shown).
When the data update completion flag (not shown) is not set in S308, that is, when both the input parameter 201 and the output parameter 203 are not updated (No in S308), the control unit 101 proceeds to S305.

When the data update completion flag (not shown) is set, that is, when the control unit 101 determines that either the input parameter 201 or the output parameter 203 has been updated (S308 Yes), the control unit 101 proceeds to S309.
In step S309, the control unit 101 calculates a SUM value for each of the input parameter 201 and the output parameter 203. That is, the control unit 101 calculates a SUM value for each of the input parameter 201 and the output parameter 203 at a predetermined cycle in which the parameter area 200 is updated (based on the determination in S308).
In S310, the control unit 101 compares the SUM value calculated from the input parameter 201 and the input parameter SUM value 202 in pairs, and calculates the SUM value calculated from the output parameter 203 and the output parameter SUM value 204. Compare the pair. When one of the SUM values compared to the pair is different, the control unit 101 determines that the parameter area 200 has been rewritten to data different from the data previously held (S310 Yes), and the data update is completed. The flag (not shown) is cleared and the process proceeds to S304. In step S304, after setting the parameters, the control unit 101 performs operation phase processing such as input / output processing.

When the SUM values compared to the pair in S310 are equal, the control unit 101 determines that the data held in the parameter area 200 is the same as the data previously held (No in S310). The data update completion flag (not shown) is cleared and the process proceeds to input processing S305.
Update data for updating parameters held in the nonvolatile memory can be stored by the communication unit 104 via the network 110 or by operating the operation unit 108. . When the data update completion flag (not shown) is in the clear state, the PLC 100 of the present invention permits rewriting of the parameter area 200 other than the control unit 101, and the data update completion flag (not shown) is in the set state. In addition, control (exclusive logic condition) is performed so that rewriting of the parameter area 200 is not permitted except for the control unit 101.
Further, according to the present invention, as a method of transmitting data update to the control unit 101, it is also possible to perform by interruption other than the exchange of flags.
In the above-described embodiment, the SUM value is described as an example of the check code for verifying the validity of the parameter. However, the programmable controller of the present invention uses a cyclically calculated code such as CRC (Cyclic Redundancy Check). It may be a check code.

By doing as described above, the present invention holds in advance a parameter (original parameter) for determining the operation mode of the PLC and a check code (original SUM value) calculated from the original parameter in the nonvolatile memory, When the PLC is operating (in operation), the control unit 101 calculates the SUM value for the update data when the update data for updating the original parameter is overwritten on the area where the original parameter is held. .
In the PLC of the present invention, the control unit 101 compares the SUM value calculated from the update data with the original SUM value, and as a result of the comparison, the operation according to the updated parameter is made due to the difference between the SUM values. Since the mode is reset, it is possible to update the parameter while the PLC is running and reflect it.
In the present invention, since the SUM value calculated from the update data is compared with the original SUM value, it is possible to accurately detect that the update data has a data pattern different from the original parameter. It was.
Further, according to the present invention, the original parameter and the original SUM value are classified into input and output (input parameter, input parameter SUM value, output parameter, output parameter SUM value), that is, a predetermined parameter connected to the programmable controller. Each device is classified in advance (group classification) and stored in a non-volatile memory, and the SUM value calculated from the input parameter is compared with the input parameter SUM value at the initial activation of the PLC (initial activation phase). Similarly, the PLC of the present invention compares the SUM value calculated from the output parameter with the output parameter SUM value. As a result, when the SUM values to be compared are different, the present invention shifts to an abnormal process (abnormal phase) without operating the PLC.

In the present invention, a group including different parameters is notified in the abnormal process (abnormal phase). In this way, the PLC according to the present invention can avoid an unexpected failure due to parameter damage, and can easily identify the damaged parameter, thereby greatly reducing the time for investigating the cause of the failure. It has become possible. Furthermore, the PLC of the present invention can save the user's burden and time for parameter update because the user only needs to repair the damaged parameter when restoring the parameter.
Further, according to the present invention, only when the parameter is normal as a result of determining whether or not the original parameter is normal by comparing the SUM values of the parameters at the initial startup (initial startup phase) of the PLC. Since the parameter is set and the operation phase is shifted to, the PLC does not operate in the wrong operation mode, and it is possible to provide a highly reliable PLC that can prevent malfunction of the PLC and prevent accidents. It has become possible.

Next, a programmable controller according to the second embodiment of the present invention will be described with reference to FIGS.
The second embodiment differs from the first embodiment described above in that the first transfer means 101d and the second transfer means 101e are added to FIG. 1 in FIG. 5, and FIG. On the other hand, an explanatory diagram of the update data area allocated to the work memory 103 (FIG. 6B) is added. In FIG. 7, S303, S311 and S312 which are program processes are added to FIG. It is in the point.
5 to 7, the same components as those in FIGS. 1 to 4 are denoted by the same reference numerals, and the description overlapping with that of the first embodiment is omitted.

FIG. 5 is an internal configuration diagram of a programmable controller according to the second embodiment of the present invention. 5 differs from FIG. 1 in that the parameters held in the nonvolatile memory (first storage means) 102 and the SUM value (first check code) are stored in the working memory (second storage means) 103. The first transfer means 101d for transferring and the parameters and the SUM value (second check code) held in the working memory (second storage means) 103 are transferred to the nonvolatile memory (first storage means) 102. The second transfer means 101e is added to the control unit 101.

That is, the control unit 101 transfers the parameters held in the nonvolatile memory (first storage unit) 102 and the SUM value (first check code) to the working memory (second storage unit) 103. Transfer means 101d, a check code calculation means 101a for adding the parameters in order to obtain a total value (SUM value), and a SUM value (first storage) transferred and held in the work memory (second storage means) 103 Check code comparing means 101b for comparing the SUM value (second check code) calculated with respect to the parameter transferred and held in the work memory (second storage means) 103, and the work memory ( The second storage means) 103 and the SUM value (second check code) held in the non-volatile memory (first storage means) The second transfer unit 101e that transfers to 02 and the parameters held in the non-volatile memory (first storage unit) 102 are referred to, and the operation mode of the control unit 101 itself is determined according to the value, and the input unit 105 and a parameter setting means 101c for giving a predetermined signal for determining the operation of the circuit to the output unit 106.
These check code calculation unit 101a, check code comparison unit 101b, parameter setting unit 101c, first transfer unit 101d, and second transfer unit 101e are all programs stored in an internal memory (not shown) of the control unit 101. It is.

FIG. 6 is a diagram illustrating memory information allocated to the nonvolatile memory 102 and the working memory 103 of the PLC 100 according to the second embodiment of the present invention. Incidentally, the working memory 103 uses an SRAM (static RAM) having a faster access time than the non-volatile memory 102 constituting the first storage means.
Schematically, the PLC 100 according to the second embodiment of the present invention configured as described above is characterized in that the access time is the parameter (original parameter) held in the nonvolatile memory (first storage means). Transfer to a fast SRAM (second storage means), update of the parameter (original parameter) is detected in this SRAM in a shorter time than the first embodiment described above, and the operation mode is restored even when the PLC is in operation. It is to set and reflect this.
The operation of the PLC according to the second embodiment of the present invention having such characteristics will be described in more detail.
FIG. 6A is a diagram showing memory information related to the parameters held in the nonvolatile memory 102 of the PLC 100, and is the same as the description of FIG.
Also, the parameters shown in FIG. 6A are classified into a plurality of groups for each predetermined device (module) connected to the programmable controller, as in FIG. 3 of the first embodiment. 200. Since the classification and parameters are the same as those in FIG. 3 of the first embodiment, the description thereof is omitted.

FIG. 6B is a diagram showing memory information allocated to the work memory 102. In this figure, reference numeral 210 denotes an update data area for the control unit 101 to save and update the input / output parameters (201, 203) and their SUM values (202, 204) held in the parameter area 200 described above. It is. The input parameter update data area 211 is an area in which the control unit 101 saves the input parameter 201 or holds update data stored by the communication unit 104 or the operation unit 108 when updating parameters. The input parameter SUM update area 212 is an area in which the control unit 101 saves data for saving the input parameter SUM value 202 or updating the SUM value 202.
The output parameter update data area 213 is an area in which the control unit 101 saves the output parameter 203 or holds update data stored by the communication unit 104 or the operation unit 108 when updating parameters. The output parameter SUM update area 214 is an area in which the control unit 101 stores data for saving the output parameter SUM value 204 or updating the SUM value 204.
FIG. 7 is a flowchart for explaining the operation of the PLC according to the second embodiment of the present invention. In this figure, the difference from FIG. 4 described in the first embodiment is that S303, S311 and S312 are added. Other processes are substantially the same as the description of FIG. 4 in the first embodiment. However, the following description is not limited to the movement different from the first embodiment and will be described in full.

In FIG. 7, after the power is turned on, the state for initialization of the PLC is set as the initial startup phase (S301 to S304), the normal operation state after the initialization is set as the operation phase (S305 and after), and the PLC is stopped. The abnormal state is defined as an abnormal phase (S320). The calculation of the SUM value described in the present embodiment, that is, the check code calculation means 101a is a program executed by the control unit 101 that adds the parameters in order and makes the total value.
In step S <b> 301, the control unit 101 calculates SUM values of the input parameters 201 and output parameters 203 classified and held for each group, and transfers them to a save area (not shown) in the control unit 101.
Next, the control unit 101 proceeds to S302, and compares the SUM value and input parameter SUM value 202 for the input parameter 201 calculated in S301, and the SUM value and output parameter SUM value 204 for the output parameter 203 calculated in S301, respectively. To do. When the SUM values compared to these pairs are equal, the control unit 101 determines that the parameter is normal, and proceeds to S303. If any one of the SUM values compared to these pairs is different, there is a high possibility that the parameter is abnormal or the nonvolatile memory is abnormal. Therefore, since it is assumed that the PLC does not operate normally when the PLC is operated as it is, the control unit 101 determines that the parameter is abnormal and shifts to S320 (abnormal phase) without operating the PLC. .

The control unit 101 that has proceeded to S320 notifies (displays) the group name including the parameter that is abnormal to the display unit 107, and the abnormality (to the other device connected to the apparatus via the network 110) Notify that the parameter is abnormal and the name of the group containing the abnormal parameter).
If it is determined in S302 that the parameters are normal, the control unit 101 proceeds to S303. In step S <b> 303, the control unit 101 transfers the input parameter 201, the input parameter SUM value 202, the output parameter 203, and the output parameter SUM value 204 to the update data area 210.
Next, the control unit 101 proceeds to S304, and refers to the input parameter 201 and the output parameter 203. In accordance with the value, the control unit 101 determines its own operation mode, and gives a predetermined signal for determining the operation of the circuit to the input unit 105 and the output unit 106. That is, the control unit 101 determines whether or not the input parameter 201 and the output parameter 203 are normal in the initial startup phase, and sets the parameters only when each parameter is normal, and the operation phase (S305 and later). Migrate to
The processing of the control unit 101 proceeds to S305, and the signal input from the input unit 105 is taken into an I / O memory (not shown) in the control unit 101 (input processing). In step S306, the control unit 101 performs a logical operation based on a program stored in advance. Next, in step S307, the control unit 101 writes the calculation execution result in the I / O memory and sends it to the output unit 106 (output processing).

After this output processing, the control unit 101 checks whether or not the data in the input parameter update data area 211 and the output parameter update data area 213 in the update data area 210 has been updated in S308 using a data update completion flag (not shown). To do.
If the data update completion flag (not shown) is not set in S308, that is, if both the input parameter update data area 211 and the output parameter update data area 213 are not updated (No in S308), the control unit 101 Shifts to S305.
When the data update completion flag (not shown) is set in S308, that is, when the control unit 101 determines that either the input parameter update data area 211 or the output parameter update data area 213 has been updated ( (S308 Yes), the process proceeds to S309.
In step S <b> 309, the control unit 101 calculates a SUM value for each update data in the input parameter update data area 211 and the output parameter update data area 213. That is, the control unit 101 performs a SUM value for each update data in the input parameter update data area 211 and the output parameter update data area 213 in a predetermined cycle in which the update data area 210 is updated (based on the determination in S308). Are calculated respectively.

In S310, the control unit 101 compares the SUM value calculated from the update data in the input parameter update data area 211 with the SUM value held in the input parameter SUM update area 212, and updates the output parameter. The SUM value calculated from the update data in the data area 213 and the SUM value held in the output parameter SUM update area 214 are compared in pairs. When any one of the SUM values compared to the pair is different, the control unit 101 determines that the update data area 210 has been rewritten with data different from the data previously held (S310 Yes). On the other hand, when all the SUM values compared with the pair are equal (S310 No), the control unit 101 determines that the data updated in the update data area 210 is the same as the data held so far (invariant). Then, the data update completion flag (not shown) is cleared, and the process proceeds to the input process S305.
Next, the process proceeds to S311. In S311, the control unit 101 transfers (writes) the update data in the update data area 210 to the parameter area 200 (nonvolatile memory 102).
For example, in S310, the control unit 101 compares the SUM value transferred to the input parameter SUM update area 212 (transferred in S303) and the SUM value calculated from the update data held in the input parameter update data area 211. To do. If the SUM values are different as a result of this comparison, the control unit 101 overwrites the input parameter SUM update area 212 with the SUM value calculated from the update data in S311 and updates the input parameter update data area 211. The data is transferred (written) to the input parameter 201, and the SUM value in the overwritten input parameter SUM update area 212 is transferred (written) to the input parameter SUM value 202.

Similarly, in S310, the control unit 101 uses the SUM value transferred to the output parameter SUM update area 214 (transferred in S303) and the SUM value calculated from the update data held in the output parameter update data area 213. Compare. If the SUM values are different as a result of this comparison, the control unit 101 overwrites the output parameter SUM update area 214 with the SUM value calculated from the update data in S311 and outputs the update data in the output parameter update data area 213. In addition to transferring (writing) to the parameter 203, the overwritten SUM value in the output parameter SUM update area 214 is transferred (written) to the output parameter SUM value 204. Of course, if each SUM value is different, both may be written.
The control unit 101 transfers (writes) the update data and its SUM value to the nonvolatile memory, and then confirms whether or not the update data has been updated in S312. If the update is successful, the control unit 101 clears the data update completion flag (not shown) and proceeds to S304 (S312 Yes). After proceeding to S304, the control unit 101 performs operation processing such as input / output processing after setting operation according to the updated parameters.
When the update cannot be performed in S312 (No in S312), the control unit 101 determines that some abnormality has occurred, such as damage to the nonvolatile memory, and proceeds to the abnormality process in S320.

In this example, the input parameter SUM update area 212 holds the data transferred with the input parameter SUM value 202 in S303, and the output parameter SUM update area 214 holds the data transferred with the output parameter SUM value 204. As explained. This is because when a non-volatile memory such as E ² PROM is used for the parameter area 200, it takes time to read data, so that the working memory 103 such as SRAM (second access time) (second access time) can be read and written. This means that the SUM value comparison check becomes faster and that the SUM value comparison program can have the same structure regardless of the type of the target nonvolatile memory. It is.
Note that the SUM value comparison method is as follows (without copying the input parameter SUM value 202 and the output parameter SUM value 204 to the working memory 103): SUM values 202 and 203 (original SUM values) stored in advance in the nonvolatile memory. The SUM calculated for the update data in the update data (211 and 212) area may be compared.
In this case, in step S <b> 310, the control unit 101 compares the input parameter SUM value 202 with the SUM value calculated from the update data held in the input parameter update data area 211. If the SUM values are different as a result of the comparison (S310 Yes), the control unit 101 transfers (writes) the update data held in the input parameter update data area 211 to the input parameter 201 in S311 and updates the above-mentioned update. The SUM value calculated from the data is written to the input parameter SUM value 202.

Similarly, in S310, the control unit 101 compares the output parameter SUM value 204 with the SUM value calculated from the update data held in the output parameter update data area 213. If the SUM values are different as a result of this comparison (Yes in S310), the control unit 101 transfers (writes) the update data held in the output parameter update data area 213 to the output parameter 203 in S311 and updates the above-mentioned update. The SUM value calculated from the data is written in the output parameter SUM value 204. Of course, if each SUM value is different, both may be written.
The update data held in the update data area 210 can be updated by the communication unit 104 being updated via the network 110 or by operating the operation unit 108. In the PLC 100 of the present invention, when the data update completion flag (not shown) is in the clear state, rewriting of the update data area 210 is permitted except for the control unit 101, and the data update completion flag (not shown) is in the set state. In some cases, control (exclusive logic condition) is performed so that rewriting of the update data area 210 is not permitted except for the control unit 101. Further, according to the present invention, as a method of transmitting data update to the control unit 101, it is also possible to perform by interruption other than the exchange of flags.

In the above-described embodiment, the SUM value is described as an example of the check code for verifying the validity of the parameter. However, the programmable controller of the present invention uses a cyclically calculated code such as CRC (Cyclic Redundancy Check). It may be a check code. By doing as described above, the present invention holds in advance a parameter (original parameter) for determining the operation mode of the PLC and a check code (original SUM value) calculated from the original parameter in the nonvolatile memory, At the initial startup of the PLC, the control unit 101 saves the original parameters and the original SUM value in the SRAM.
Then, when the PLC is operating (in operation), the control unit 101 calculates the SUM value for the updated data when the original parameter saved in the SRAM is updated to the update data for updating the original parameter. To do.
The PLC of the present invention compares the calculated SUM value with the original SUM value saved in the SRAM, and as a result of the comparison, the SUM value is different, so that the original parameter held in the nonvolatile memory and the original SUM value are compared. The SUM value is rewritten. Since the PLC of the present invention resets the operation mode in accordance with the updated parameter, it is possible to update the parameter during the operation of the PLC and reflect it.

In the present invention, since the SUM value calculated from the update data is compared with the SUM value (copy of the original parameter) held in the SRAM, the update data has a data pattern different from the original parameter. Can be accurately detected in a short time.
In addition, since the present invention updates the parameters based on the comparison result of the SUM values, it can suppress the update of the parameters to the nonvolatile memory (prevent unnecessary writing), and thus has a long lifetime. It became possible to provide PLC.
Further, according to the present invention, the original parameter and the original SUM value are classified into input and output (input parameter, input parameter SUM value, output parameter, output parameter SUM value), that is, a predetermined parameter connected to the programmable controller. Each device is classified in advance (group classification) and stored in a non-volatile memory, and the SUM value calculated from the input parameter is compared with the input parameter SUM value at the initial activation of the PLC (initial activation phase). Similarly, the PLC of the present invention compares the SUM value calculated from the output parameter with the output parameter SUM value. As a result, when the SUM values to be compared are different, the present invention shifts to an abnormal process (abnormal phase) without operating the PLC.

Further, according to the present invention, a group including different parameters is notified in the abnormal process (abnormal phase). In this way, the PLC according to the present invention can avoid an unexpected failure due to parameter damage, and can easily identify the damaged parameter, thereby greatly reducing the time for investigating the cause of the failure. It has become possible. Furthermore, the PLC of the present invention can save the user's burden and time for parameter update because the user only needs to repair the damaged parameter when restoring the parameter.
In the present invention, when the PLC is initially started (initial startup phase), the parameter SUM value is compared to determine whether the original parameter is normal. As a result, the parameter is set only when the parameter is normal. Because the PLC has been set to shift to the operation phase, it is possible to provide a highly reliable PLC that does not operate in the wrong operation mode, prevents the PLC from malfunctioning, and prevents accidents. It became.

It is an internal block diagram which shows the structure of the programmable controller (PLC) based on Example 1 of this invention. It is a block diagram which shows the memory information in the programmable controller (PLC) based on Example 1 of this invention. It is a table | surface which shows the example based on Example 1 of this invention that the parameter is classified into a some group. It is a flowchart which shows the process which a control part performs according to Example 1 of this invention. It is an internal block diagram which shows the structure of the programmable controller (PLC) based on Example 2 of this invention. It is a block diagram which shows the memory information in the programmable controller (PLC) based on Example 2 of this invention. It is a flowchart which shows the process which a control part performs according to Embodiment 2 of this invention.

Explanation of symbols

100 Programmable controller (PLC)
DESCRIPTION OF SYMBOLS 101 Control part 101a Check code calculation means 101b Check code comparison means 101c Parameter setting means 101d First transfer means 101e Second transfer means 102 Non-volatile memory 103 Work memory 104 Communication part 105 Input part 106 Output part 107 Display part 108 Operation Part 109 Internal bus 110 Network 200 Parameter area (nonvolatile memory)
201 Input Parameter 202 Input Parameter SUM Value 203 Output Parameter 204 Output Parameter SUM Value 210 Update Data Area (Work Memory)
211 Input parameter update data area 212 Input parameter SUM update area 213 Output parameter update data area 214 Output parameter SUM update area

Claims (6)

A programmable controller that reads a parameter for determining an operation mode and operates by setting an operation mode according to the parameter ,
First storage means in which the parameter and a first check code for verifying the validity of the parameter are stored in advance;
A first transfer means for transferring the parameter held in the first storage means to a second storage means;
When a flag indicating that the parameter held in the second storage unit has been updated is set, in order to verify the validity of the parameter from the parameter updated in the parameter stored in the second storage unit Check code calculation means for calculating the second check code of
Check code comparing means for comparing the first check code and the second check code ;
When the check code comparing means determines that the first check code and the second check code are different, the parameter stored in the second storage means is updated and the second check A second transfer means for respectively transferring a code to the first storage means and overwriting the parameter and the first check code previously held in the first storage means;
A parameter setting unit that reads a parameter overwritten by a parameter previously stored in the first storage unit, and resets the operation mode;
A programmable controller comprising: A programmable controller that reads a parameter for determining an operation mode and operates by setting an operation mode according to the parameter ,
First storage means in which the parameter and a first check code for verifying the validity of the parameter are stored in advance;
First transfer means for transferring the parameter and the first check code held in the first storage means to the second storage means, respectively;
When a flag indicating that the parameter held in the second storage unit has been updated is set, in order to verify the validity of the parameter from the parameter updated in the parameter stored in the second storage unit Check code calculation means for calculating the second check code of
Check code comparison means for comparing the first check code held in the second storage means with the second check code;
When it is determined by the check code comparison means that the first check code held in the second storage means is different from the second check code, the parameters held in the second storage means The updated parameter and the second check code are respectively transferred to the first storage unit, and the parameter and the first check code previously stored in the first storage unit are overwritten. Transfer means,
A parameter setting unit that reads a parameter overwritten by a parameter previously stored in the first storage unit, and resets the operation mode;
A programmable controller comprising: The programmable controller according to claim 1, wherein
The parameter and the first check code are classified into a plurality of groups in advance for each predetermined device connected to the programmable controller and held in the first storage unit,
The check code calculation means calculates a check code for verifying the validity of each parameter for each of the classified and held parameters at the initial startup of the programmable controller,
The check code comparison means compares the calculated plurality of check codes with the first check code corresponding to the check code, respectively.
The programmable controller further causes the parameter setting means to set the parameter when it is determined by the check code comparison means that the check codes match. The programmable controller according to claim 1, wherein
The parameter and the first check code are classified into a plurality of groups in advance for each predetermined device connected to the programmable controller and held in the first storage unit,
The check code calculation means calculates a check code for verifying the validity of each parameter for each of the classified and held parameters at the initial startup of the programmable controller,
The check code comparison means compares the calculated plurality of check codes with the first check code corresponding to the check code, respectively.
The programmable controller further includes notification means for notifying the group including the different check code when the check code comparison means determines that the check code is different.
A programmable controller comprising: The first or second check code is a SUM value obtained by sequentially adding the parameters, or a value obtained by cyclic calculation of the parameters. Programmable controller. The programmable controller according to claim 1, wherein the first storage unit is a rewritable nonvolatile memory.

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