JP2016130947A - Control system and control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid arising of unnecessary processing narrowing down an execution band of an application program in equalization.SOLUTION: A redundant control system has a pair of control devices formed, each control device which performs equalization at each execution period of an application program is provided with a memory interface circuit which functions as data management means, and a control unit of the control device is made to function as transmission means and reception means. The data management means manages whether data is updated after last equalization for each piece of data stored in a memory. The transmission means executes, at each execution period, processing to read data, updated after the last equalization, out of the memory and to transmit the data to the other control device when serving as an in-operation system. The reception means executes processing to update data received from the other control device and stored in a self memory as data corresponding to the received data when serving as a standby system.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control system in which control devices for controlling devices are duplicated, and more particularly to a technique for equalizing calculation results by the control devices.

In industrial facilities such as factories and various plants, a communication system called a control system is often constructed to control various operations. The control system includes a control device that collects monitoring data from sensors installed in an industrial facility and performs drive control of an electric motor or the like according to the collection result. Such control devices include DCS (Distributed).
Control System: a distributed control system or a distributed control device) or a programmable logic controller (hereinafter, PLC) is used. In a general FA (Factory Automation) system, PLC is often used as a control device, and in plant facilities that require high reliability, DCS is often used as a control device. This is because DCS is more reliable than PLC.

  In this type of control system, there is a case where the control device is duplicated in order to avoid the operation stop caused by the failure of the control device. Specifically, two control devices are provided in the control system, and one of them is operated as an active system and the other as a standby system. Hereinafter, a control system in which control devices are duplicated is referred to as a “redundant control system”. The active control device executes a predetermined calculation for device control according to the application program, and the standby control device prepares for the stop of the active control device. The standby control device then operates as an active system when the active control device stops (or stops). As a specific example of the stop of the active control device, an unexpected stop due to the occurrence of some failure or malfunction, a planned stop due to maintenance, etc. can be considered. The standby control device provides for both of these two types of stops. In such a redundant control system, in order to enable each of the two control devices to monitor the other state, the two control devices are often connected via a communication cable.

  In the redundant control system, even if a failure occurs in the active control device, the operation system / standby system is switched to continue the operation for controlling the control target device and the control according to the operation result. However, there are cases where problems such as sudden changes in the calculation results occur before and after switching between active and standby systems. In order to avoid the occurrence of such a problem, in the redundant control system, an equalization process for transmitting and storing the operation result in the active system to the standby system via the communication cable is periodically executed. More specifically, in the redundant control system, a series of processes executed according to the application program (monitoring data collection, calculation of control data based on the monitoring data, transmission of control data, etc.) The process is called a tact), and the tact and the subsequent equalization process are repeatedly executed at a constant cycle as shown in FIG. As a result, it is possible to avoid an operation stop caused by a failure of the control device while preventing a sudden change in the calculation result before and after switching between the active system and the standby system. Hereinafter, the fixed period is referred to as an “application execution period”, and the communication cable is referred to as an “equalization cable”.

  The flow of equalization processing executed every application execution cycle is as follows. A control unit (for example, a microcomputer) of the active control device writes the result of calculation according to the application program in its own memory. The control unit of the operating system control device stores the data stored in the storage area that is the target of equalization among the data stored in its own memory at the equalization timing such as the end time of the tact. Copy to the communication buffer of its own communication interface. The data copied to the communication buffer in this way is transmitted to the standby control device via the equalization cable. The standby control device expands the data received via the equalization cable in the memory area that is the target of equalization in its own memory. This completes the equalization process.

JP 2000-148525 A

  The application execution cycle in the redundant control system may be determined with a sufficient margin (that is, longer than the sum of the two) with respect to the sum of the time required for the tact execution and the time required for the equalization processing. Many. However, the update cycle of data updated in accordance with the application program in the redundant control system does not necessarily match the application execution cycle, and a part of the storage area to be equalized is stored at the execution timing of the equalization process. Only the content may be updated. In the example shown in FIG. 8, the storage areas AREA0 to AREA3 are equalization targets. In the application execution cycle T1 in FIG. 8, the data is updated for all the storage areas to be equalized, but in the application execution cycle T2, the data in the storage areas AREA0 and AREA2 is not updated, and the application execution cycle T3. In FIG. 4, data in all storage areas to be equalized is not updated.

  It goes without saying that the data in the storage area that has not been updated need not be copied to the communication buffer or transmitted to the standby system. However, in the conventional redundant control system, copying to the communication buffer and transmission to the standby system have been performed for all storage areas that are targeted for equalization, regardless of whether or not the data has been updated. In other words, the equalization processing in the conventional redundancy control system includes wasteful processing, and a period (hereinafter referred to as application program) that can be allocated to tacts within the application execution cycle by the amount of execution of the wasteful processing. There is a problem that the execution band) is compressed, and this problem is particularly remarkable in a redundant control system for plant control. The reason is as follows. One of the factors that cause the variation in the data update cycle as described above is whether the monitoring data transmission source (or control data transmission destination) is a digital device or an analog device. In general, the data input / output cycle differs for each device, but the data input / output cycle of a digital device is often shorter than the data input / output cycle of an analog device. Plant facilities often include both digital devices and analog devices, and in addition to their variety, the application execution cycle is 200 milliseconds to 1 second, which is longer than FA systems. Therefore, the above problem appears remarkably.

  The present invention has been made in view of the above problems, and an object thereof is to provide a technique for avoiding the occurrence of useless data transmission that narrows the execution band of an application program in equalization processing in a redundant control system. And

  In order to solve the above-described problems, the present invention provides the following application to each control device of a control system including two control devices, one of which is an active system and the other is a standby system and performs communication via the equalization communication means. An execution unit, a data management unit, a transmission unit, and a reception unit are provided. The application execution means executes the application program at a predetermined cycle, and writes data generated in the execution process to a storage area in the memory. The data management means stores, for each storage area of the memory, an identifier indicating whether data has been updated since the previous communication for equalization. The transmission means reads out the data in the storage area in which the identifier indicating that there is an update from the data stored in the memory and is stored in the data management means and transmits the data to the other control device by itself. In some cases, it is executed every execution cycle of the application program. The receiving means executes a receiving process for updating data stored in its own memory as data corresponding to the data received from the other control device, when it is a standby system.

  In the communication for equalization executed at each execution period of the application program in the control system of the present invention, only the data updated after the previous equalization process among the data to be equalized is the active system. The data is transmitted from the control device to the standby control device, and the standby control device copies only the data received from the active system to the memory. For this reason, in the control system of the present invention, useless data (that is, data that has not been updated since the previous equalization process) is not transmitted and copied as compared with the conventional redundant control system. Therefore, it is possible to allocate bandwidth to the execution of the application.

  In Patent Document 1, for each command to be executed by the control device, which of the active system (active system) and the standby system is set as a processing device is determined in advance for each command, and processing is performed by the active system and the standby system. A technique for reducing the processing load of the active system by distributing is disclosed. However, the technique disclosed in Patent Document 1 is not a technique for avoiding the occurrence of useless data transmission from the active system to the standby system, and is a technique completely different from the present invention.

  As another aspect of the present invention, in place of the transmission means, a process of transmitting a pair of data stored in a memory and the identifier corresponding to the data to the other control device is an active system. In some cases, each control device is provided with a transmission means that executes every execution cycle of the application program, and is paired with an identifier indicating that there is an update from the data received from the other control device instead of the reception means. There may be a mode in which each control device is provided with a receiving unit that executes a process of updating data stored in its own memory as data corresponding to the data when it is a standby system. Even in such a mode, useless data (that is, data that has not been updated since the previous equalization process) is not copied as compared with the conventional redundant control system, and the application is accordingly increased. Bandwidth can be allocated to the execution of

  The following two modes are conceivable as specific modes of bandwidth allocation for application program execution in the execution cycle of the application program and bandwidth allocation for equalization processing. First, the application program is executed after performing equalization processing on the execution result of the application program in the immediately preceding time interval. Second, the execution of the application program and the equalization process for the execution result are performed in this order. In the case of the latter mode, the application execution unit causes the application program to be executed over a period of time determined in advance for each execution cycle of the application program, and the contents stored in the data management unit at the end of the period are stored. Accordingly, the process for extending the period may be executed, and the transmission means may be made to execute the transmission process after the execution of the application program by the application execution means in the application program execution cycle. Further, during the extended period, the execution of the previous application program may be continued, or another application program selected according to a predetermined priority order may be executed.

  In order to solve the above problems, the present invention provides the following control device as a control device for a redundant control system. Like the control device in the conventional redundant control system, this control device forms a control device pair in which one is an active system and the other is a standby system, and communicates via an equalization communication means. The control device of the present invention includes the following control unit and memory interface circuit. The control unit executes the application program every execution cycle of the application program, and writes data generated in the execution process to a storage area in the memory. The memory interface circuit mediates data exchange between the memory and the control unit.

  The memory interface circuit includes the following table and an address decoding circuit. In the table, an identifier indicating whether or not data has been updated since the previous equalization process is stored for each storage area of the memory. The address decoding circuit writes data to the memory in accordance with a data write instruction from the control unit and updates the stored contents of the table. Further, the address decoding circuit reads from the memory the data instructed to be read from the control unit, and returns it to the control unit together with an identifier corresponding to the data. When the control unit itself is an active system, the control unit transmits data that is paired with an identifier indicating that there is an update from the data read through the memory interface circuit to the other control device. A memory interface that executes processing for each execution cycle of an application program and updates data stored in a storage area corresponding to the data with data received from the other control device when the system is a standby system A reception process instructing the circuit is executed.

  If such a control device is used to form a control device pair in a redundant control system, useless data (that is, data that has not been updated since the previous equalization process) compared to a conventional redundant control system. ) Transmission and copying, and it is possible to allocate bandwidth to application execution accordingly. Also in this aspect, instead of the transmission process, the transmission process for transmitting the data acquired via the memory interface circuit and the identifier indicating the presence / absence of the update of the data to the other control device is executed, Instead of the above reception process, a reception process for instructing the memory interface circuit to update the data stored in its own memory as data corresponding to the data paired with the identifier indicating that there is an update. You may make it perform.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to avoid generation | occurrence | production of the useless data transmission which narrows the execution band of an application program by the equalization process in a redundancy control system.

1 is a block diagram illustrating a configuration example of a control device 10 according to an embodiment of the present invention and a configuration example of a control system including the control device 10. FIG. 3 is a block diagram illustrating a configuration example of a memory I / F circuit 110 included in the control device 10. FIG. 3 is a diagram illustrating a configuration example of an address match detection circuit 1140 (n) included in the memory I / F circuit 110. FIG. 3 is a diagram showing an example of the contents stored in an update register 116 included in the memory I / F circuit 110. FIG. It is a figure which shows the operation example of this embodiment. It is a figure for demonstrating the equalization data of this embodiment. It is a figure for demonstrating a modification (1). It is a figure for demonstrating the equalization process in the conventional redundant control system.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration example of a control device according to an embodiment of the present invention and a configuration example of a control system including the control device. This control system is laid in an industrial facility such as a plant, performs drive control of a control target device (for example, an electric motor or the like) based on monitoring data collected from a sensor or the like installed in the industrial facility, and the industrial facility It is a system that supports the operation of As shown in FIG. 1, the control system includes a control device 10 </ b> A and a control device 10 </ b> B each connected to a control network 30. Although detailed illustration is omitted in FIG. 1, the control network 30 is connected to a sensor or the like serving as a monitoring data transmission source and a control target device. The sensors and devices to be controlled connected to the control network 30 may be a mixture of both digital devices and analog devices, or only one of them.

  As shown in FIG. 1, the control device 10 </ b> A and the control device 10 </ b> B are connected to each other via an equalization cable 20. In the control system shown in FIG. 1, one of the control device 10A and the control device 10B becomes an active system and performs an operation for drive control of the control target device, and the other becomes a standby system and an active system. Prepare for failure. That is, the control system shown in FIG. 1 is a redundant control system. Below, the case where 10 A of control apparatuses are an active system is demonstrated. Each of the control devices 10A and 10B is, for example, a DCS. As shown in FIG. 1, the configuration of the control device 10A and the configuration of the control device 10B are the same. For this reason, in the following, when it is not necessary to distinguish between the control device 10A and the control device 10B, they are referred to as “control device 10”. In the present embodiment, since the controlled object is plant equipment, DCS is used as the control device 10, but it goes without saying that PLC may be used.

  The control device 10 includes a control unit 100, a memory I / F circuit 110, a memory 120, and a communication I / F circuit 130. The control unit 100 is a microcomputer. The control unit 100 functions as a control center of the control device 10 by executing a control program stored in advance in a nonvolatile memory (not shown). For example, the control unit 100 operating according to the control program executes various calculations for controlling the operation of the control target device according to the application program stored in advance in the nonvolatile memory, and stores the calculation result data in the memory. Write to 120. That is, the control unit 100 operating according to the control program functions as an application execution unit that executes an application program and writes data of the execution result in the memory 120. Functions realized by operating the control unit 100 according to the control program include an initialization function and an equalized data generation / expansion function in addition to an application calculation function for executing an application program.

  The initialization function refers to initialization of the memory I / F circuit 110, the communication I / F circuit 130, and the memory 120 at the time of starting up the control system (more precisely, when the control device 10 is turned on). Parameter setting and address assignment). The equalized data generation / expansion function is a function for realizing the above-described equalization processing. Among the three functions realized by operating the control unit 100 according to the control program, the features of the present embodiment appear in the application calculation function and the equalized data generation / expansion function. Details of the application calculation function and the equalized data generation / expansion function will be clarified in the operation example in order to avoid duplication.

  The memory 120 is a volatile memory such as a RAM (Random Access Memory). As shown in FIG. 1, the memory 120 is connected to the control unit 100 via the memory I / F circuit 110. The memory 120 is provided with a plurality of storage areas, and the control unit 100 designates a logical address (hereinafter simply referred to as “address”) assigned to each storage area in the initialization process, thereby storing the corresponding memory address. It is possible to read data stored in the area and write data to the storage area (hereinafter, both may be collectively referred to as “access”). In some of the plurality of storage areas of the memory 120, data to be equalized with the other control device 10 is written. In the present embodiment, an area name ARAn (n = 0 to N: N is a natural number) is assigned to a storage area in which data to be equalized is written, and each storage area is identified by these area names. In the following, a case where the address adr (n) is assigned to the storage area of the area name AREAN by the above-described initialization function will be described.

  The memory I / F circuit 110 is an LSI that mediates access by the control unit 100 to various data stored in the memory 120. FIG. 2 is a block diagram illustrating a configuration example of the memory I / F circuit 110. As shown in FIG. 2, the memory I / F circuit 110 includes two registers (an address table register 112 and an update register 116 as shown in FIG. 2) and an address decoding circuit 114.

  The address table register 112 is a register that stores an address indicating a storage destination in the memory 120 of data to be equalized with the other control device 10. As shown in FIG. 2, the address table register 112 has N (N = 15 in the example shown in FIG. 2) +1 storage areas, and one address is stored in each storage area. For example, the address adr (n) is stored in the nth storage area of the address table register 112. Writing each address to the address table register 112 is realized by the initialization function of the control unit 100.

  The update register 116 is an N + 1 bit register. The nth bit b (n) of the update register 116 corresponds to the storage area indicated by the address adr (n). In the present embodiment, the most significant bit of the update register is b (15), and the least significant bit is b (0). Each bit of the update register 116 is initialized to “0” by the initialization function of the control unit 100. The nth bit b (n) of the update register 116 is updated to “1” when the data in the storage area indicated by the address adr (n) is updated. That is, the nth bit b (n) of the update register 116 serves as an identifier indicating whether or not the data in the storage area indicated by the address adr (n) is updated.

  The address decoding circuit 114 is a circuit that specifies the storage position in the memory 120 of the data indicated by the address given from the control unit 100 and reads and writes the data. Then, the address decoding circuit 114 updates the stored contents of the update register 116 in response to a data write instruction from the control unit 100, and updates whether the data instructed to be read from the control unit 100 is updated. A process of notifying the control unit 100 with reference to the contents stored in 114 and the update register 116 is executed. Further, when the control unit 100 notifies the completion of the equalization process, the address decoding circuit 114 resets all the configuration bits of the update register 116 to “0”. That is, the address decoding circuit 114 of this embodiment plays a role of a data management unit that stores an identifier indicating whether or not data has been updated since the previous data communication for equalization for each storage area of the memory 120. .

  As shown in FIG. 2, the address decoding circuit 114 includes address match detection circuits 1140 (n) (n = 0 to N) corresponding to the storage areas of the address table register 112, respectively. In FIG. 2, reference numerals other than 1140 (0) and 1140 (15) are omitted in order to avoid the drawing from becoming complicated. An address output from the control unit 100 to the memory I / F circuit 110 for designating a data write destination is given to one input terminal of the address match detection circuit 1140 (n), and the other input terminal receives An address (that is, an adr (n) address) stored in the nth storage area of the address table register 112 is given. Various specific examples of the configuration of the address match detection circuit 1140 (n) can be considered. When adr (n) is an address of M (arbitrary natural number) bits, the configuration shown in FIG. Conceivable.

  FIG. 3 shows a configuration example of the address match detection circuit 1140 (n) when M = 16. As shown in FIG. 3, the address match detection circuit 1140 (n) includes M Ex-NOR circuits 1140a (n) (m) (m = 0 to M−1), an AND circuit 1140 (n) b, It is comprised by. As shown in FIG. 3, the m-th bit of the address output from the control unit 100 (indicated as in (m) in FIG. 3) is connected to one input terminal of the Ex-NOR circuit 1140a (n) (m). And the m-th bit of the address adr (n) (indicated as adr (n) (m) in FIG. 3) is given to the other input terminal. As is well known, the output signal of the Ex-NOR circuit is “1” when the input signals to both input terminals match, and “0” when they do not match. As shown in FIG. 3, the output signal of the Ex-NOR circuit 1140a (n) (m) (m = 0 to M-1) is given to the AND circuit 1140b (n), and the output signal of the AND circuit 1140b (n). Becomes the output signal of the address coincidence detection circuit 1140 (n). Therefore, when the addresses given to the two input terminals of the address match detection circuit 1140 (n) match, the signal value of the output signal of the address match detection circuit 1140 (n) becomes “1”, If they do not match, it is “0”.

  The output terminal of the address match detection circuit 1140 (n) is connected to the nth bit b (n) of the update register 116. Therefore, when the data indicated by the address adr (n) is updated, the value of the nth bit b (n) of the update register 116 is updated to “1”. For example, after the initialization by the initialization function, when the data indicated by the address adr (3) and the data at the address adr (1) are updated, the contents stored in the update register 116 are updated as shown in FIG.

Returning to FIG. 1, the communication I / F circuit 130 is an LSI for data communication, is connected to the control network 30, and communicates with the communication I / F of the other control device 10 via the equalization cable 20. The circuit 130 is connected. Of the data communication executed by the communication I / F circuit 130, the data communication with the control network 30 is not related to the present embodiment and has no particular difference from that in the conventional control device. Therefore, the description is omitted. Although detailed illustration is omitted in FIG. 1, the communication I / F circuit 130 includes a transmission buffer for storing data to be transmitted to the other control device 10 and a reception buffer to which data received from the other control device 10 is written. Have. In the active control device 10, the data to be equalized is written to the transmission buffer of the communication I / F circuit 130 by the above-described equalized data generation / expansion function. The communication I / F circuit 130 of the active control device 10 transmits the data written in the transmission buffer as described above to the standby control device 10 via the equalization cable 20. On the other hand, the communication I / F circuit 130 of the standby control device 10 writes the data received via the equalization cable 20 to the reception buffer, and the control unit 100 of the standby control device 10 In this way, the data stored in its own memory 120 is updated (that is, equalized) using the data stored in the reception buffer.
The above is the configuration of the control device 10.

  Next, details of the application calculation function and the equalized data generation / expansion function will be described in accordance with the operation of the present embodiment. The application calculation function is a function for executing an application program over a period of a predetermined time length TD in the application execution cycle, and this point is not particularly different from the application calculation function in the conventional control device. The application calculation function of the present embodiment refers to the contents stored in the update register 116 when the above period expires, and the smaller the number of bits whose value is “1” (that is, the unupdated equalization target) The more data), the longer the extension period and the longer the period.

  In FIG. 5, N = 3 (that is, data stored in the total of four storage areas AREA0 to AREA3 is a target of equality), and the value in the update register 116 at the end of the period of the time length TD. An example of operation in the case where the number of bits of “0” × time length ΔT is an extension width is shown. In the application execution cycle T1 in FIG. 5, since all the data to be equalized are updated and all the configuration bits of the update register 116 are 1 at the end of the period of the time length TD, the period is extended. Is not done. On the other hand, in the application execution cycle T2, when the period of the time length TD expires, two of the data to be equalized are updated, and two of the configuration bits of the update register 116 are “0”. Therefore, the above-mentioned period extension is extended by 2 × ΔT. In the application execution cycle T3, the data to be equalized is not updated at the end of the period of the time length TD, and the configuration bits of the configuration bits of the update register 116 are all “0”. The period extension is extended by 4 × ΔT, and the execution of the equalization process is omitted.

  Here, the extension width corresponding to the stored contents of the update register 116 may be set to a suitable value through appropriate experiments. As will be described later, in the equalized data generation / expansion function of this embodiment, only data that has been updated since the previous equalization process is copied to the transmission buffer in the active system, and from the active system to the standby system. And the expansion to the memory 120 in the standby system is performed. Therefore, the more data that has not been updated, the shorter the time required for the equalization processing. Therefore, if the extension width is appropriately determined, there is a problem that the equalization processing is not completed within the application execution cycle even if the extension width is increased as the number of unupdated equalization target data increases. There is nothing. In the present embodiment, the period is extended by the extension width corresponding to the number of bits having a value of “0” in the update register 116 at the end of the period of the time length TD, but the update register at the end of the period If all of the constituent bits of 116 are not “1”, it is extended by a predetermined time length ΔT, and whether or not re-extension is possible at the end of the extension period depends on the contents stored in the update register 116. The determination process may be repeated, and the time interval for determining whether re-extension is possible may be narrowed as updated data increases.

  Next, the equalized data generation / expansion function will be described in detail. The control unit 100 of the active control device 10 first reads the stored contents of the update register 116 via the memory I / F circuit 110 after completion of execution of the application program by the application calculation function. Next, the control unit 100 of the active control device 10 reads the data in the storage area in which “1” is set in the configuration bit of the update register 116 from the memory 120 via the memory I / F circuit 110. Then, the control unit 100 of the active control device 10 generates equalized data using the contents stored in the update register 116 and the data read from the memory 120 as described above, and communicates the equalized data. Write to the transmission buffer of the I / F circuit 130.

  FIG. 6A is a diagram showing an example of equalized data when N = 15. In the equalized data, as shown in FIG. 6A, a data identifier in which the constituent bits of the update register 116 are arranged in order from the most significant bit to the least significant bit is arranged at the head, and the array of these identifiers is followed. Data corresponding to each identifier is arranged. FIG. 6A illustrates the equalized data when the AREA3 data and the AREA1 data are updated. In this case, the content stored in the update register 116 is “0000000000001010” (0x000A in hexadecimal notation), so 0x000A is set as the data identifier. This data identifier indicates that two pieces of data follow the data identifier and that the two pieces of data are AREA3 and AREA1 data. As described above, the communication I / F unit 130 of the active control device 10 transfers the data stored in the transmission buffer (equivalent data in this embodiment) via the equalization cable 20 to the standby system. It transmits to the control apparatus 10.

  That is, in the present embodiment, only the data that has been updated since the previous equalization process was executed among the data to be equalized is transmitted from the active control device 10 to the standby control device 10, etc. The data identifier included in the value data serves to transmit to the standby control device 10 which of the data to be equalized has been updated. In this embodiment, the data having the data structure shown in FIG. 6A is used as the equalization data transmitted from the active control device 10 to the standby control device 10, but FIG. As shown in FIG. 6, equalization data in which each data to be equalized is divided by a separator SP (for example, a tab code) and arranged may be used. In such equalization data, the continuous separator means that the data between them has not been updated. Therefore, any of the data to be equalized is updated without using the array of identifiers. It can be transmitted to the standby control device 10. In addition, as communication between the active control device 10 and the standby control device 10, after synchronization by a Sync message or the like, predetermined data is transmitted for each time slot (for example, the time slot immediately after the Sync) Is used only for AREA15 data, the next time slot is dedicated for AREA14, etc.), and when only updated data is transmitted, each data can be identified by the time slot. In this case as well, there is no need to use the identifier.

  The equalized data transmitted from the active control device 10 to the standby control device 10 is stored in the reception buffer of the communication I / F unit 130 of the standby control device 10. The communication I / F unit 130 of the standby control device 10 reads the equalized data stored in the reception buffer and provides the same to the control unit 100. The control unit 100 of the standby control device 10 refers to the equalized data delivered from the communication I / F unit 130, refers to the data identifier included in the equalized data, and updates the updated data. And the data stored in its own memory 120 as corresponding to the data is updated (overwritten) with the received data.

  As described above, according to this embodiment, it is possible to avoid occurrence of useless data copy and useless data transmission in the equalization processing in the redundancy control system, and to maximize the execution bandwidth of the application program. Can be assigned to the limit.

Although one embodiment of the present invention has been described above, it goes without saying that the following modifications may be added to this embodiment.
(1) In the above embodiment, the address table register 112 and the update register 116 are separate registers. However, as shown in FIG. 7, a table in which both are integrated (data update since the previous communication for equalization) The memory I / F circuit 110 may store an update identifier indicating whether or not there is an update identifier for each storage area of the memory. As described above, even if the address table register 112 and the update register 116 are integrated, the memory I / F circuit 110 provides an identifier indicating whether or not data has been updated since the previous communication for equalization in the memory. This is because it functions as data management means for storing each storage area.

(2) In the above embodiment, only the data updated after the previous equalization process is transmitted from the active control device 10 to the standby control device 10 among the data to be equalized, and the active system The controller 10 updates the corresponding data of its own device with the data received via the equalization cable. However, all the data to be equalized is transmitted from the active control device 10 to the standby control device 10 in pairs with the constituent bits of the update register 116 regardless of whether or not the update is performed. The control device 10 may update the corresponding data of its own device with data received via the equalization cable 20 only for data paired with the flag indicating that there is an update. Even in such an aspect, the wasteful data copy in the standby control device 10 (copying from the reception buffer to the memory 120 in the standby control device for the unupdated data) is eliminated and the equalization processing is performed. This is because it is possible to reduce the required bandwidth and allocate the bandwidth to the execution of the application program accordingly.

  In this aspect, although the processing load of the active control device 10 is lighter than that of the above embodiment, data transmission from the active control device 10 to the standby control device 10 via the equalization cable is performed. A wide communication band is required. For this reason, when priority is given to reducing the processing load of the active control device 10, it is preferable to adopt this aspect, and from the active control device 10 via the equalization cable to the standby control device. When priority is given to the reduction of the communication band for data transmission to 10, the embodiment of the above embodiment is preferable.

(3) In the above-described embodiment, a case has been described in which, in each application execution cycle, first, the application program is executed over a predetermined period TD, and then equalization processing is executed. However, in each application execution cycle, the data updated by the execution of the application program in the previous application execution cycle may be equalized, and the remaining time may be allocated to the execution of the application program. Even in such an aspect, it is possible to eliminate unnecessary data copy in the active control device 10 to reduce the bandwidth required for the equalization processing, and to allocate the bandwidth to the execution of the application program accordingly. It is. Further, in such an aspect, since the period that can be allocated to the execution of the application program in each application execution cycle is known before the start of the execution, the stored contents of the update register 116 are referred to as in the above embodiment, It is not necessary to determine whether the period can be extended.

(4) One or more application programs may be executed by the control unit 100 in the application execution cycle. In a mode in which a plurality of application programs are executed, a priority order is determined in advance for each application program, and the control unit 100 executes in a predetermined time length period TD and an extended period in each application execution cycle. The application program to be selected may be selected according to the priority order. The application program with the highest priority is executed in the period TD, and the application program with the lower priority is executed in the extended period. For example, when executing two types of application programs that require equalization processing and application programs that do not require equalization processing, the former priority is set high, the former is executed during the period TD, and the extension period So that the latter is executed. According to such an aspect, the update register 116 is not updated by the execution of the latter application program, and the execution of the application program is avoided while avoiding the occurrence of a situation where time for equalization processing is insufficient. It becomes possible to allocate the maximum bandwidth.

(5) In the above embodiment, the redundant control system in which the control device pair is formed by the control device 10 which is one of the embodiments of the present invention has been described. However, the control device 10 is provided alone (that is, manufactured and sold). ) This is because the existing redundant control system can function as the control system of the present invention by replacing each control device forming a control device pair with the control device 10 in the existing redundant control system.

  DESCRIPTION OF SYMBOLS 10, 10A, 10B ... Control apparatus, 20 ... Equalization cable, 30 ... Control network, 100 ... Control part, 110 ... Memory I / F circuit, 112 ... Address table register, 114 ... Address decoding circuit, 11140 (n) (N = 0 to N) ... address match detection circuit, 1140a (n) (m) (m = 0 to M) ... EX-NOR circuit, 1140b (n) ... AND circuit, 116 ... update register, 120 ... memory, 130: Communication I / F circuit,

Claims (6)

A control system comprising two control devices, one of which is an active system and the other is a standby system, which communicates via an equalization communication means,
Each of the two control devices
An application execution means for executing an application program in a predetermined cycle and writing data generated in the execution process to a storage area in the memory;
Data management means for storing, for each storage area of the memory, an identifier indicating the presence or absence of data update since the previous communication for equalization;
When the data stored in the memory is an active system that performs the transmission process of reading the data in the storage area in which the identifier indicating the update is stored in the data management means and transmitting it to the other control device Transmitting means for executing each execution cycle of the application program;
Receiving means for executing a receiving process for updating data stored in its own memory as data corresponding to the data received from the other control device, when it is a standby system. And control system. A control system comprising two control devices, one of which is an active system and the other is a standby system, which communicates via an equalization communication means,
Each of the two control devices
An application execution means for executing an application program in a predetermined cycle and writing data generated in the execution process to a storage area in the memory;
Data management means for storing, for each storage area of the memory, an identifier indicating the presence or absence of data update since the previous communication for equalization;
Transmission that executes transmission processing for transmitting the data stored in the memory and the identifier corresponding to the data to the other control device to the other control device every execution cycle of the application program. Means,
Among the data received from the other control device, the standby system performs a receiving process for updating the data stored in its own memory as data corresponding to the data that is paired with the identifier indicating that there is an update. And a receiving means for executing the control system. The application execution unit executes the application program over a period of a predetermined time length for each execution cycle of the application program, and sets the period according to the stored contents of the data management unit at the end of the period. Execute the extension process,
The control system according to claim 1, wherein the transmission unit executes the transmission process after the execution of the application program by the application execution unit is completed in an execution cycle of the application program. A plurality of application programs executed by the application execution means, each having a plurality of application programs each having a priority order;
The control system according to claim 3, wherein the application execution unit selects an application program to be executed in the predetermined time length period and the extended period according to the priority order. A control device that forms a control device pair composed of two control devices in which one is an active system and the other is a standby system and communicates through an equalization communication means,
A control unit that executes an application program in a predetermined cycle and writes data generated in the execution process to a storage area in the memory;
A memory interface circuit that mediates data exchange between the memory and the control unit,
The memory interface circuit includes:
A table that stores, for each storage area of the memory, an identifier indicating the presence or absence of data update since the previous communication for equalization;
In response to a data write instruction from the control unit, data is written to the memory and the stored contents of the table are updated, while data instructed to be read from the control unit is read from the memory, and the data And an address decoding circuit that sends a reply to the control unit together with an identifier corresponding to
The controller is
If the system itself is an active system, the process of transmitting the data paired with the identifier indicating that there is an update from the data read through the memory interface circuit to the other control device While running every
In the case of a standby system, the memory interface circuit is instructed to update the data stored in the storage area corresponding to the data with the data received from the other control device. Control device. A control device that forms a control device pair composed of two control devices in which one is an active system and the other is a standby system and communicates through an equalization communication means,
A control unit that executes an application program in a predetermined cycle and writes data generated in the execution process to a storage area in the memory;
A memory interface circuit that mediates data exchange between the memory and the control unit,
The memory interface circuit includes:
A table that stores, for each storage area of the memory, an identifier indicating the presence or absence of data update since the previous communication for equalization;
In response to a data write instruction from the control unit, data is written to the memory and the stored contents of the table are updated, while data instructed to be read from the control unit is read from the memory, and the data And an address decoding circuit that sends a reply to the control unit together with an identifier corresponding to
The controller is
If the system itself is an active system, the process of transmitting the data read through the memory interface circuit and the identifier to the other control device as a pair is executed every execution period of the application program,
In the case of the standby system, the data received from the other control device is paired with an identifier indicating that there is an update, and the data stored in its own memory is updated as corresponding to the data. A control device that executes a process for instructing the memory interface circuit to

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