JP6921344B1 - Control system - Google Patents

Abstract

The control system (1) includes an IPC (2) for processing data obtained at the production site and a PLC (3) for sequence-controlling the equipment (4B) at the production site according to a ladder program. The PLC (3) is provided with a linking unit (24, 32) for linking the operations, respectively, and the IPC (2) partially performs a ladder program to the PLC (3) when the PLC (3) is in an overloaded state. ) Is executed to sequence control the device (4B) together with the PLC (3).

Description

The present disclosure relates to a control system that controls a controlled device.

Conventionally, there has been known a technique that realizes high-speed control processing and load distribution by using a plurality of processors and each processor controls a device in parallel. Patent Document 1 describes a distributed control system including a plurality of control processors and determining the division of program execution of each control processor so that the processing load of each control processor is equalized.

Japanese Unexamined Patent Publication No. 2000-259589

The distributed control system described in Patent Document 1 can distribute the processing load among the same type of processors, each of which has the same function, but cannot distribute the processing load among different types of processors. For example, the distributed control system described in Patent Document 1 includes, in addition to the control processor, a host controller that downloads a program to the control processor, monitors control information, and the like. The processing load cannot be distributed among them. That is, in the distributed control system described in Patent Document 1, when the processing load of each of the plurality of control processors is high and the processing load of the host controller is low, the host controller executes the program instead of the control processor. It is not possible to reduce the processing load of the control processor.

The present disclosure has been made in view of the above, and an object of the present invention is to obtain a control system that controls a device by distributing a processing load among different types of devices.

In order to solve the above-mentioned problems and achieve the object, the control system according to the present disclosure includes a computer that processes data obtained at the production site, a control device that sequence-controls the equipment at the production site according to a ladder program, and the like. Each of the computer and the control device includes a control device and a coordinating unit for coordinating operations according to a data processing flow indicating a series of data processing flows executed by the computer and the control device. When the control device becomes overloaded, the computer converts a part of the ladder program into a program in a format that can be executed by itself, and inserts information indicating data processing performed by executing the converted program into the data processing flow. Then, the data processing flow is changed, and the sequence control of the device is shared with the control device according to the changed data processing flow.

The control system according to the present disclosure has an effect that the processing load can be distributed among different types of devices to control the devices.

The figure which shows the configuration example of the control system which concerns on embodiment The first figure which shows the operation of a control system The second figure which shows the operation of the control system Flow chart showing an example of the overall operation of the control system

Hereinafter, the control system according to the embodiment of the present disclosure will be described in detail with reference to the drawings.

Embodiment.
FIG. 1 is a diagram showing a configuration example of a control system according to an embodiment. The control system 1 includes an IPC (Industrial Personal Computer) 2 which is an industrial computer and a PLC (Programmable Logic Controller) 3 which is a programmable logic controller. The device 4A is connected to the IPC2, and the device 4B is connected to the PLC3. The device 4A is, for example, a sensor installed at a production site. The device 4B is, for example, a robot installed at a production site. In the example shown in FIG. 1, the devices connected to the control system 1 are two devices 4A and 4B, but the number of devices connected to the control system 1 may be three or more, or even one device. good. Further, the number of PLC3s included in the control system 1 may be two or more. That is, the control system 1 may have a configuration in which two or more PLC3s are connected to one IPC2.

Here, the control system 1 is a system located in the edge computing area or the manufacturing site area. The control system 1 realizes a series of processes for collecting data from the devices 4A and 4B installed at the production site and feeding back the processing result data to the devices 4A and 4B at the production site based on the data processing result of the collected data. Has a data processing platform. The edge computing area is a concept that means a computing area located at the edge of cloud computing, and is a system area that manages a manufacturing site in a factory. In the edge computing area, advanced data processing is performed on the data obtained at the production site. In addition, advanced data processing in the edge computing area means to perform data processing using an advanced data analysis method with respect to the data analysis method at the manufacturing site. For example, table calculation software is used at the manufacturing site. In contrast to performing data analysis using AI, in the edge computing area, it means performing data analysis for predictive maintenance using AI (Artificial Intelligence).

IPC2 is provided for the purpose of data processing. That is, in the edge computing domain, IPC2 is used as an edge computing device. IPC2 is an electronic computer that processes data obtained at the production site. On the other hand, the PLC 3 is a control device provided for the purpose of controlling the equipment at the production site, and performs sequence control of the equipment according to a ladder program. In addition to the data acquired by the sensor, the IPC2 also collects data from, for example, the PLC3, generates a command according to the diagnosis result which is the data processing result, and transmits the command to the controlled device via the PLC3. Cooperation between IPC2 and PLC3 is important for the utilization of data at the production site.

In the control system 1, IPC2 and PLC3 cooperate to realize flexible data processing. That is, in the control system 1, it is possible to perform consistent settings from data collection to data processing and diagnosis, and device control, that is, data processing flow settings. The data processing flow is a processing flow showing a series of data processing flows for realizing a series of data processing by combining a plurality of processes. Here, in the control system 1, the data processing flow is set in the IPC2, but the data processing flow is executed in cooperation with the IPC2 and the PLC3. In addition, IPC2 collects, processes and diagnoses data, and PLC3 not only controls the equipment, but also IPC2 collects and processes data when there is a large surplus of PLC3 resources due to the stoppage of the controlled equipment. It may be configured so that the PLC3 performs diagnosis and control of the device. In addition, the IPC2 may perform data collection, processing, diagnosis, and a part of control, and the PLC3 may perform the remaining control.

Further, in the control system 1, IPC2 and PLC3 share a ladder program and execute distributed processing according to their respective load conditions to realize sequence control of devices. Here, sharing the ladder program means that the PLC3 has the ladder program and a part of the ladder program is passed to the IPC2. Passing a part of the ladder program to the IPC2 means that the IPC2 copies a part of the ladder program. Not limited to this, IPC2 may implement a part of the ladder program in a different programming language. When passing a part of the ladder program of PLC3 to IPC2, the output of the ladder program of PLC3 and the input of the ladder program received by IPC2 are matched, and the output of the ladder program of IPC2 and the ladder program of PLC3 are matched. The input interface of the PLC is matched, and the ladder program can be executed in cooperation with the PLC3 and the IPC2.

The IPC2 includes data processing units 21A and 21B that perform various data processing in the data processing flow, data collection units 22A and 22B that collect data at the production site from PLC3 and other devices 4A and 4B, and a data processing flow. A data processing execution control unit 23 that performs execution control such as distributing data between the data collection units 22A and 22B and the data processing units 21A and 21B according to the above is provided. The data processing execution control unit 23 has a data distribution unit 30 that distributes data between the data collection units 22A and 22B and the data processing units 21A and 21B. The data distribution unit 30 distributes the data required by each of the data collection units 22A and 22B and the data processing units 21A and 21B based on desired settings. In the present embodiment, the number of the data processing unit and the data collecting unit included in the IPC2 is two, but the configuration may include three or more, or one. Also, the number of data processing units and data collection units does not have to be the same. For example, the data collected by one data collecting unit may be processed by a plurality of data processing units, the data collected by the plurality of data processing units may be processed by one data processing unit, and the like.

The IPC2 includes a cooperation unit 24 that links data processing with the PLC3, a program execution unit 25 that executes a part of the ladder program that operates on the PLC3, a ladder program that is executed by the program execution unit 25, and a ladder program that is executed by the PLC3. Further includes a synchronization unit 26 that synchronizes the sequence processing with the above, and an engineering tool 27 for the user to set the IPC2 and the PLC3. The engineering tool 27 manages the data processing flow executed by the IPC2 and the ladder program executed by the PLC3, and provides the user with a function for creating and editing each of the data processing flow and the ladder program. In the present embodiment, the IPC2 is provided with the engineering tool 27, but the engineering tool 27 may be provided outside the IPC2.

Each component of the IPC2 is realized by executing a program for the CPU (Central Processing Unit) 200 mounted on the IPC2 to operate as each component of the IPC2.

Here, when the execution base of the data processing flow and the execution base of the ladder program are different, it may be difficult to execute the ladder program operating on the PLC3 on the IPC2. Therefore, the program execution unit 25 is provided with a virtual infrastructure which is a virtualized infrastructure, and the execution infrastructure for the ladder program is mounted on the virtual infrastructure so that the ladder program can be executed. The program execution unit 25 is configured so that a plurality of execution platforms can be prepared. For example, when the ladder program operates on the software PLC (S / W-PLC), the program execution unit 25 prepares an execution platform (OS: Operating System) for the S / W-PLC, and also prepares the ladder program. When the PLC3 operates on the ASIC (Application Specific Integrated Circuit) of the PLC, a module for converting the operation of the ASIC into software is prepared.

The cooperation unit 24 monitors the processing status of the IPC2 and the PLC3 and the program conversion unit 28 that converts a part of the ladder program executed by the PLC3 into a program in a format that can be executed by the IPC2, and each of them shares and executes the ladder program. A sharing ratio determining unit 29 for determining the ratio to be used is provided.

On the other hand, the PLC 3 includes a ladder execution unit 31 that executes the ladder program, a cooperation unit 32 that cooperates with the IPC 2, and a synchronization unit 33 that synchronizes the sequence processing timing of the ladder program executed by the IPC 2 with the IPC 2.

Each component of the PLC 3 is realized by executing a program for the CPU 300 mounted on the PLC 3 to operate as each component of the PLC 3.

Here, in the IPC2, the program conversion unit 28 identifies the location of the ladder program executed by the IPC2 among the ladder programs executed by the PLC3, and converts the specified location into a program in a format that can be executed on the IPC2. For example, the program conversion unit 28 specifies a part of the ladder program (RA unit in the example shown in FIG. 2) as a program to be executed by IPC2 as shown in FIG. 2, and further specifies as shown in FIG. A part of the ladder program is executed by the program execution unit 25, and the data processing flow is executed by the data processing execution control unit 23 and the data processing units 21A and 21B. Further, the program conversion unit 28 creates a data processing flow to be executed by IPC2 by inserting the converted program (FA unit shown in FIG. 3) into the data processing flow. Note that FIG. 2 is a first diagram showing the operation of the control system. In the operation shown in FIG. 2, the PLC 3 executes up to the RA portion of the ladder program to control the device 4B, and the IPC 2 subsequently executes the collection process, the processing process, and the diagnostic process. Further, FIG. 3 is a second diagram showing the operation of the control system. In the operation shown in FIG. 3, after the processing by the PLC 3 is completed, the IPC 2 first executes the FA unit obtained by converting the RA unit shown in FIG. 2 of the ladder program to control the device 4B, and then controls the device 4B. Execute collection processing, processing processing, and diagnostic processing. When the operation shown in FIG. 2 is changed to the operation shown in FIG. 3, the IPC2 now executes a part of the processing previously executed by the PLC3 instead, and the processing load of the PLC3 is reduced.

When converting the ladder program into a format that can be executed by IPC2, the program conversion unit 28 inserts a command to end the process executed by PLC3 into the ladder program and a command to start the process by IPC2. As a result, the program conversion unit 28 separates the program portion executed by the PLC 3 and the program portion executed by the IPC 2. Next, the program conversion unit 28 inserts a command for starting execution of the program on the IPC2 into the program on the IPC2 side, that is, the converted program. For example, the program conversion unit 28 inserts a command indicating a position to start the program into the program on the IPC2 side when the notification that the execution of the program on the PLC3 side is completed is received. As a result, the IPC2 can execute a program corresponding to the ladder program as a series of processes in cooperation with the PLC3. The program corresponding to the ladder program is a program obtained by converting the ladder program into a format that can be executed by IPC2. Next, when the program conversion unit 28 uses the device value of the ladder program executed on the PLC3 side in the ladder program executed on the IPC2 side, the device value used in the ladder program on the PLC3 side for the program executed on the IPC2 side. To assign. As a result, the program conversion unit 28 generates a data processing flow to which a program corresponding to a ladder program that can be executed by IPC2 is added.

Further, the program conversion unit 28 uses the sharing ratio determined by the sharing ratio determining unit 29, which will be described later, when separating the program portion for executing the ladder program on the PLC3 and the program portion for executing the ladder program on the IPC2. That is, the program conversion unit 28 separates the ladder program into two according to the sharing ratio determined by the sharing ratio determining unit 29. The program conversion unit 28 separates the ladder program by using the sharing ratio, but the PLC3 executes the ladder program after the separation so that the arithmetic unit, which is the CPU 300 of the PLC3, does not have an excessive margin due to the separation. Check the operating rate of the case, and separate the ladder program so that the CPU resources of PLC3 can be used preferentially. That is, the program conversion unit 28 determines the location of the ladder program to be executed by the IPC 2 so that the CPU resources of the PLC 3 can be used preferentially.

Further, the program conversion unit 28 notifies the cooperation unit 32 of the PLC3 of the location of the ladder program to be executed by the IPC2. Upon receiving this notification, the cooperation unit 32 of the PLC3 knows that the ladder program is ready to be executed by the IPC2. The ladder program executed by IPC2 is a program that can be executed by IPC2 that realizes the same function as the ladder program executed by PLC3. However, IPC2 does not prevent the execution of the ladder program.

The sharing ratio determination unit 29 monitors the sequence scan time due to the execution of the ladder program in PLC3, and adjusts the sharing ratio when it is determined that the sharing ratio needs to be adjusted. When the sequence scan time is extended, the sharing ratio determining unit 29 determines that it is necessary to adjust the sharing ratio because it means that processing within the processing capacity of the CPU 300 mounted on the PLC 3 is difficult. When the sequence scan time is extended, the share ratio determination unit 29 is increased in order to maintain the sequence scan time in PLC3 based on, for example, the elongation rate of the sequence scan, that is, the time extended from the initial sequence scan time. The sharing ratio for causing the IPC2 to bear the processing for the time taken is used as the sharing ratio result. Here, the share ratio result refers to the ratio of the processing distribution of the ladder program between PLC3 and IPC2. For example, when the elongation rate of the sequence scan is 30%, the increased processing of 30% is the ladder in IPC2. Transfer to program processing.

The sharing ratio determination unit 29 may not only monitor the growth rate of the sequence scan time, but may also determine the sharing ratio result based on the operating rate of the CPU 300 of the PLC 3 or the memory usage (usage rate). When the sharing ratio determination unit 29 calculates the sharing ratio based on the operating rate of the CPU 300 or the amount of memory used, the ratio of the operating rate of the CPU 300 of the PLC 3 and the CPU 200 of the IPC 2 or the use of the memory of the PLC 3 and the memory of the IPC 2 It may be calculated based on the percentage of the rate. When the CPU performances of PLC3 and IPC2 are different, the sharing ratio determining unit 29 calculates the sharing ratio in consideration of the performance.

Subsequently, the flow of the cooperative processing of IPC2 and PLC3 will be described with reference to FIG. FIG. 4 is a flowchart showing an example of the overall operation of the control system.

First, the user uses the engineering tool 27 to create a ladder program and set the data processing flow (step S1). When the work by the user is completed, the engineering tool 27 writes the ladder program and the data processing flow to the data processing execution control unit 23. Next, the data processing execution control unit 23 transfers the ladder program to the cooperation unit 24, and the cooperation unit 24 writes the ladder program to the PLC 3 (step S2).

Then, when the PLC3 and the IPC2 receive the data processing start signal by a user operation or the like, they start the sequence processing and the data processing flow realized by the ladder program, respectively (step S3). When the processing is started in step S3, the PLC3 and the IPC2 execute the sequence processing and the data processing flow, respectively (step S4). These sequence processing and data processing flows are repeatedly executed together with steps S5 to S9 until it is determined that the sequence processing and data processing flow are completed in step S6 described later.

Note that the PLC 3 operates so as to sequentially execute all the processes described in the ladder program at the start of the process, that is, at the time when the step S4 is first executed. After that, when the location of the ladder program executed by the IPC2 is notified from the IPC2, the PLC3 operates so as to execute a process other than the location executed by the IPC2 among the processes described in the ladder program.

Following step S4, the synchronization unit 26 of IPC2 and the synchronization unit 33 of PLC3 perform synchronization processing (step S5). The synchronization process of step S5 is performed when the IPC2 performs a part of the ladder program, that is, a part of the sequence control. In the synchronization process, the synchronization unit 26 of the IPC2 notifies the synchronization unit 33 of the PLC3 when the execution process by the program execution unit 25 of the program obtained by converting a part of the ladder program is completed. Upon receiving this notification, the synchronization unit 33 instructs the ladder execution unit 31 to execute the part in charge of the ladder program. Similarly, when the execution process by the ladder execution unit 31 of the ladder program is completed, the synchronization unit 33 of the PLC3 notifies the synchronization unit 26 of the IPC2 of this. Upon receiving this notification, the synchronization unit 26 instructs the program execution unit 25 to execute a program obtained by converting a part of the ladder program.

After executing the synchronization process, IPC2 and PLC3 confirm whether the operation is terminated, that is, whether the operation is instructed to be stopped by the user operation or the like (step S6), and when the operation stop is instructed (step S6: Yes), stop the operation. When the stop of the operation is not instructed (step S6: No), the share ratio determination unit 29 of the IPC2 confirms the load status of the PLC3 (step S7), and determines whether the PLC3 is in the overload state (step S8). As described above, the sharing ratio determining unit 29 determines whether the PLC 3 is in the overloaded state based on, for example, the sequence scan time. That is, the sharing ratio determination unit 29 determines that the PLC 3 is in an overloaded state when the sequence scan time is extended.

When the PLC3 is in the overloaded state (step S8: Yes), the load is adjusted between the IPC2 and the PLC3 (step S9). That is, in the cooperation unit 24 of the IPC2, the sharing ratio determination unit 29 determines the sharing ratio, and based on this sharing ratio, the program conversion unit 28 executes the ladder program on the PLC3 and the program portion on the IPC2. Separate into and. The ladder program is separated by the method described above. After the load adjustment is performed, the process returns to step S4, and IPC2 and PLC3 continue step S4 and the subsequent processing. In this case, in step S4, the sequence control is shared according to the result of the load adjustment. If the PLC3 is not in the overloaded state (step S8: No), the process returns to step S4, and the IPC2 and PLC3 continue the step S4 and the subsequent processing.

As described above, the control system 1 according to the present embodiment includes an IPC 2 for processing data obtained at the production site and a PLC 3 for controlling the device 4B at the production site, and the IPC 2 and the PLC 3 are the devices 4B. A means for linking control operations (coordination unit 24, cooperation unit 32) is provided. When the PLC3 is in an overloaded state, the IPC2 executes a part of the ladder program in place of the PLC3 and controls the sequence of the device 4B together with the PLC3. The control system 1 can distribute the processing load related to the control of the device 4B between the IPC2 and the PLC3.

The configuration shown in the above embodiment is an example, and can be combined with another known technique, or a part of the configuration may be omitted or changed without departing from the gist. It is possible.

1 Control system, 2 IPC, 3 PLC, 4A, 4B equipment, 21A, 21B data processing unit, 22A, 22B data collection unit, 23 data processing execution control unit, 24, 32 cooperation unit, 25 program execution unit, 26, 33 Synchronization unit, 27 engineering tools, 28 program conversion unit, 29 sharing ratio determination unit, 30 data distribution unit, 31 ladder execution unit, 200, 300 CPU.

Claims (7)

A computer that processes data obtained at the production site,
A control device that sequence-controls equipment at the production site according to a ladder program,
With
The computer and the control device each include a linking unit for linking operations according to a data processing flow indicating a series of data processing flows executed by the control device and itself.
When the control device becomes overloaded, the computer converts a part of the ladder program into a program in a format that can be executed by itself, and executes the converted program to perform data processing. The data processing flow is changed by inserting it into the processing flow, and the sequence control of the device is shared with the control device according to the changed data processing flow.
A control system characterized by that. The computer is
A program conversion unit that converts a part of the ladder program into a program in a format that can be executed by the computer.
The control system according to claim 1, wherein the control system comprises. The computer and the control device each include a synchronization unit that synchronizes the timing of the control device to sequence control the device and the timing of the computer to sequence control the device.
The control system according to claim 1 or 2. The computer is
A sharing ratio determination unit that determines the ratio at which the control device and the computer each share and execute the ladder program when the control device is in an overloaded state.
The control system according to any one of claims 1 to 3, wherein the control system comprises. The sharing ratio determining unit determines the ratio based on the amount of change in time required for sequence control of the device by the control device.
The control system according to claim 4. The sharing ratio determining unit determines the ratio based on the operating rate of the arithmetic unit included in the control device.
The control system according to claim 4. The sharing ratio determining unit determines the ratio based on the usage rate of the memory included in the control device.
The control system according to claim 4.

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