JP7589598B2 - CONTROL SYSTEM, SUPPORT METHOD AND PROGRAM - Google Patents

Description

This disclosure relates to a control system, a support method, and a program.

At various manufacturing sites, control systems that include a control device such as a PLC (Programmable Logic Controller) and multiple communication slaves connected to the control device are being introduced. At manufacturing sites, there may be a demand to increase the scale of the control system. If the current PLC's capabilities are insufficient to meet such demands, it may be possible to replace it with a high-performance PLC. For this reason, vendors that provide PLCs need to develop a wide variety of products according to the scale of the control system.

In recent years, distributed controller systems have been developed that connect multiple PLCs via a network and send and receive data between the PLCs to perform collaborative and synchronous operations (see JP 2010-097624 A (Patent Document 1)). By using a distributed controller system, it is possible to accommodate an increase in the scale of the control system by adding PLCs of the same model as existing PLCs. This allows the number of types of products that vendors need to prepare to be reduced.

JP 2010-097624 A

When building a distributed controller system using multiple PLCs, work is required to optimize the communications within the control system and the calculations of each PLC. Patent Document 1 does not take into consideration the efficiency of such work.

This disclosure has been made in consideration of the above problems, and its purpose is to provide a control system, support method, and program that can efficiently optimize communications and the calculation content of each control device.

According to one example of the present disclosure, a control system for controlling a control target includes a plurality of communication slaves and a plurality of control devices operating as communication masters. Each of the plurality of control devices includes a processor. The control system includes a division means, a scheduling means, and a calculation means. The division means divides a user program for controlling the control target into a plurality of partial programs. For each of a plurality of combinations in which the plurality of partial programs are assigned to the plurality of control devices, the scheduling means determines a communication schedule for each of the plurality of control devices and a calculation schedule for each of the processors of the plurality of control devices using information indicating the connection relationships between the plurality of control devices and the plurality of communication slaves and the assigned partial programs. The calculation means calculates an evaluation value according to the communication schedule and the calculation schedule for each of the plurality of combinations.

According to this disclosure, by referring to the evaluation values, the user can determine the suitability of the communication schedule and calculation schedule of each control device for multiple combinations. As a result, the user can efficiently optimize the communications within the control system and the calculation content of each control device.

In the above disclosure, the control system further includes a selection means for selecting one combination from among the multiple combinations based on the evaluation value, and a setting means for setting the partial program assigned to one combination in each of the multiple control devices.

According to this disclosure, a partial program can be installed in the control device according to one combination selected based on the evaluation value.

In the above disclosure, each of the multiple control devices executes communication of input/output data with at least one of the multiple communication slaves and calculations using the input/output data for each predetermined control period. The multiple control devices include a first control device and a second control device. The control system further includes an adjustment means for adjusting the time difference between the start timing of the control period in the first control device and the start timing of the control period in the second control device in accordance with the communication timing between the first control device and the second control device.

According to this disclosure, the time difference between the start timing of the control cycle in the first control device and the start timing of the control cycle in the second control device is adjusted according to the communication timing between the first control device and the second control device, thereby reducing the occurrence of unnecessary waiting time.

In the above disclosure, the user program includes a monitoring program that monitors input data from multiple communication slaves. The multiple control devices include a first control device to which the monitoring program is not assigned, and a second control device to which the monitoring program is assigned. The scheduling unit sets the communication method from any one of the multiple communication slaves to the first control device to multicast, with the first control device and the second control device specified as destinations. Furthermore, the scheduling unit incorporates a read time for reading the input data transmitted by multicast into the communication schedule of the second control device.

According to this disclosure, the communication method is set to multicast, which makes communication in the control system more efficient.

In the above disclosure, each of the multiple control devices executes communication of input/output data with at least one of the multiple communication slaves and calculations using the input/output data for each predetermined control period. The control system further includes an adjustment means for adjusting the time difference between the start timing of the control period in the first control device and the start timing of the control period in the second control device in accordance with the read time.

This disclosure reduces the occurrence of unnecessary waiting time. As a result, communication in the control system becomes more efficient.

In the above disclosure, each of the multiple control devices transmits output data to at least one of the multiple communication slaves for each predetermined control period. The setting unit further identifies a first timing that is the latest among the timings at which the output data arrives at the multiple communication slaves within the control period based on the communication schedule of each of the multiple control devices determined for one combination, and sets a second timing at which the multiple communication slaves start processing to be after the first timing. According to this disclosure, the processing of the multiple communication slaves can be synchronized.

According to another example of the present disclosure, a support method for supporting a control system that controls a control target includes first to third steps. The first step is a step of dividing a user program for controlling the control target into multiple partial programs. The second step is a step of determining, for each of multiple combinations in which multiple partial programs are assigned to multiple control devices, a communication schedule for each of the multiple control devices and a calculation schedule by each processor of the multiple control devices using information indicating the connection relationships between the multiple control devices and the multiple communication slaves and the assigned partial programs. The third step is a step of calculating an evaluation value according to the communication schedule and the calculation schedule for each of the multiple combinations.

According to another example of the present disclosure, a program causes a computer to execute the above support method.

These disclosures also enable users to efficiently optimize communications within a control system and the calculations of each control device.

This disclosure allows users to efficiently optimize communications within a control system and the calculations of each control device.

FIG. 1 is a diagram illustrating an example of a control system to which a support device according to an embodiment is applied. FIG. 13 is a diagram showing an example of increasing the scale of a control system. FIG. 1 illustrates an example of a scaled-up control system using a distributed controller system. FIG. 2 is a diagram showing a process flow in a distributed controller system. FIG. 2 illustrates an example of a hardware configuration of a support device. FIG. 2 is a diagram illustrating an example of a hardware configuration of a PLC. FIG. 2 illustrates an example of a functional configuration of a support device. FIG. 13 is a diagram illustrating an example of a variable list. FIG. 2 is a diagram showing an example of modules included in the control system shown in FIG. 1 . FIG. 13 is a diagram illustrating an example of a definition of an operation. FIG. 13 is a diagram illustrating an example of a calculation block incorporated in a user program. FIG. 13 is a diagram showing a part of a user program created in accordance with the definition of operations and allocation information. FIG. 13 is a diagram illustrating an example of dividing a user program into a plurality of partial programs. FIG. 11 is a diagram showing an example of a partial program divided from a user program. A diagram showing one of multiple combinations identified by a scheduling unit. FIG. 2 is a diagram illustrating an example of communication performed in a control system. FIG. 13 is a diagram showing frame communication performed in combination (2). FIG. 2 is a diagram showing an example of a communication schedule for IO data in a PLC. FIG. 2 is a diagram showing an example of allocation of various programs included in a user program to tasks. FIG. 11 is a diagram showing an example of a schedule determined by a scheduling unit. FIG. 11 is a diagram showing another example of allocation of various programs included in a user program to tasks. FIG. 13 is a diagram showing another example of a schedule determined by the scheduling unit. 13 is a diagram showing a schedule of PLC 200a in a combination (1) in which partial programs 222d and 222e are assigned to PLC 200a. FIG. FIG. 13 is a diagram showing the schedules of PLCs 200a and 200b in the case of combination (2). 11 is a diagram showing an example of an evaluation value calculated from a communication schedule and a calculation schedule; FIG. FIG. 13 is a diagram showing another example of an evaluation value calculated from a communication schedule and a calculation schedule. FIG. 13 illustrates another example of communication implemented in the control system. FIG. 13 is a diagram showing the schedules of PLCs 200a and 200b when a partial program 222e includes a monitoring program in combination (2). FIG. 11 illustrates an example of a method for setting a processing schedule of a communication slave.

Embodiments of the present invention will now be described with reference to the drawings. In the following description, identical parts and components are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of these will not be repeated. Note that the embodiments and variations described below may be combined as appropriate.

§1. Application Example An outline of a control system according to the present embodiment will be described. Fig. 1 is a diagram showing an example of a control system according to the present embodiment. A control system 1 illustrated in Fig. 1 controls various control targets such as a robot, a transport device, and a safety device.

As shown in FIG. 1, the control system 1 includes a support device 100, multiple PLCs 200, multiple communication slaves 300, and one or more switches 400. The PLC 200 is an example of a control device that operates as a communication master. In the example shown in FIG. 1, the multiple PLCs 200 include PLCs 200a and 200b. The multiple communication slaves 300 include communication slaves 300a to 300i. However, the number of PLCs 200 is not limited to two, and may be three or more. The number of communication slaves 300 is not limited to eight, and may be two or more.

In the control system 1, TSN (Time-Sensitive Networking) technology is adopted to synchronize the multiple PLCs 200. TSN technology is a network technology for interoperating industrial networks and information networks that extend standard Ethernet (registered trademark), and is based on Ethernet (registered trademark), ensuring time synchronization and real-time performance. The specifications of TSN technology are defined by the network standard "IEEE 802.1 AS-Rev Timing and Synchronization for Time-Sensitive Applications". Scheduling of TSN is handled by a PLC that functions as a network controller and has a CNC (Central Network Controller) implemented among the multiple PLCs 200. Alternatively, the control system 1 may include a network controller connected to the switch 400. In this case, the network controller may perform TSN scheduling.

The PLC 200 includes a CPU (Central Processing Unit) unit having a processor 202. Furthermore, the PLC 200 may further include expansion units such as a communication unit and a safety unit. The communication slave 300 is a device such as an input/output device.

Each of the multiple PLCs 200 communicates input/output data (IO data) with at least one of the multiple communication slaves 300 and performs calculations using the IO data at each predetermined control period.

Switch 400 is, for example, an L2 switch. Switch 400 stores the MAC addresses of connected devices and transmits data only to the destination using the MAC address.

The support device 100 supports the control system 1. The support device 100 is an information processing device (an example of a computer) that assists the multiple PLCs 200 in making the necessary preparations to control the control targets.

Specifically, the support device 100 executes a support process to support communication between the PLCs 200 and optimization of the calculation contents of each PLC 200. The support process includes the following steps (1) to (3).

(1) The support device 100 divides a user program for controlling a control target into multiple partial programs.

(2) The support device 100 identifies multiple combinations in which multiple partial programs are assigned to multiple PLCs 200. The support device 100 acquires connection information indicating the connection relationship between the multiple PLCs 200 and the multiple communication slaves 300. For each of the multiple combinations, the support device 100 uses the connection information and the assigned partial programs to determine a communication schedule for each PLC 200 and a calculation schedule for the processor 202 of each PLC 200.

(3) The support device 100 calculates an evaluation value for each of the multiple combinations according to the communication schedule and the calculation schedule.

By checking the evaluation values calculated by the above support process, the user can determine the suitability of the communication schedule of each PLC 200 and the calculation schedule by the processor 202 of each PLC 200 among multiple combinations. As a result, the user can efficiently optimize the communication within the control system 1 and the calculation content of each PLC 200.

The support device 100 may also provide a development environment for user programs (program creation and editing tools, parsers, compilers, etc.), a configuration environment for setting parameters (configurations) for multiple PLCs 200 and multiple communication slaves 300, and the like. The support device 100 provides these environments using known technology. Therefore, details of providing the development environment and the configuration environment will not be described.

§2. Specific examples <A. Increase in the scale of control systems>
2 is a diagram showing an example of increasing the scale of a control system, in which the number of modules, each of which is made up of two communication slaves 300 associated with each other, is increased from one to three.

The control system 1X before the scale increase includes a PLC 200X and a module Ma. A user program 122X for controlling the module Ma is installed in the PLC 200X.

After the scale increase, the control system 1Y further includes modules Mb and Mc in addition to module Ma. PLC 200X does not have the ability to control the three modules Ma, Mb, and Mc. Therefore, the control system 1Y is equipped with a high-performance PLC 200Y instead of PLC 200X. A high-performance PLC 200Y is generally expensive. Therefore, the cost of replacing PLC 200X with PLC 200Y is high. Furthermore, a vendor that provides PLCs will need to develop a wide variety of PLCs according to the scale of the control system.

A user program 122Y for controlling modules Ma, Mb, and Mc is installed in PLC 200Y. Since modules Ma, Mb, and Mc are controlled by a single PLC 200Y, user program 122Y may include processes for enabling and disabling each module. This makes it time-consuming to create user program 122Y.

As such, when PLC200X is replaced with a high-performance PLC200Y as the scale of the control system increases, problems arise in that costs and the effort required to create user programs increase.

Figure 3 is a diagram showing an example of a control system whose scale has been increased by using a distributed controller system. The control system 1Z shown in Figure 3 includes modules Ma, Mb, and Mc, PLCs 200Xa, 200Xb, and 200Xc that control modules Ma, Mb, and Mc, respectively, and a switch 400Z. The switch 400Z switches communication between the PLCs 200Xa, 200Xb, and 200Xc.

In control system 1Z, PLCs 200Xa, 200Xb, and 200Xc each control one module, and therefore only need to have the same performance as PLC 200X in control system 1X shown in FIG. 2. Therefore, when increasing the scale from control system 1X to control system 1Z, it is sufficient to add two inexpensive PLCs 200X.

Furthermore, the user can create user program 122Z by combining programs 122Za, 122Zb, and 122Zc for controlling modules Ma, Mb, and Mc, respectively. Programs 122Za, 122Zb, and 122Zc are then installed in PLCs 200Xa, 200Xb, and 200Xc, respectively. Therefore, the user can omit adding module enablement and disablement processes when creating user program 122Z. As a result, the effort required to create a user program is reduced.

In this way, by using a distributed controller system, the increase in costs required for PLCs and the effort required to create user programs can be suppressed. However, as the number of communication slaves and PLCs included in a control system increases, work must be done to optimize the communications within the control system and the calculation contents of each PLC. For this reason, the support device 100 according to this embodiment supports the work of optimizing the communications within the control system and the calculation contents of each PLC.

<B. Processing flow in the distributed controller system>
Fig. 4 is a diagram showing a process flow in the distributed controller system. Fig. 4 shows a process flow of the PLCs 200a and 200b when a distributed controller system is constructed using the PLCs 200a and 200b.

First, in steps S1a and S1b, PLCs 200a and 200b correct the time of their internal timers. This synchronizes the internal timers of PLCs 200a and 200b.

Next, PLCs 200a and 200b start the operation of the scheduler (steps S2a and S2b). PLCs 200a and 200b perform address resolution (steps S3a and S3b).

Next, the PLCs 200a and 200b perform a comparison with the connected communication slave 300 (steps S4a and S4b). Depending on the comparison result, the PLCs 200a and 200b establish a connection with the connected communication slave 300 (steps S5a and S5b).

Next, the PLCs 200a and 200b transmit and receive a synchronization trigger (steps S6a and S6b). In response to the synchronization trigger, the PLCs 200a and 200b start communication (S7a and S7b). This synchronizes the communication processes of the PLCs 200a and 200b.

C. Hardware Configuration
(C-1. Hardware configuration of the support device)
FIG. 5 is a diagram showing an example of the hardware configuration of the support device. As shown in FIG. 5, the support device 100 includes a CPU 102, a ROM (Read Only Memory) 103, a RAM (Random Access Memory) 104, a HDD (Hard Disk Drive) 105, a communication controller 107, and an I/O (Input/Output) interface 108. A keyboard 109 and a display 110 are connected to the support device 100. The keyboard 109 accepts inputs including instructions from a user to the support device 100. To accept the inputs, other devices such as a mouse may be connected to the support device 100. The display 110 includes an LCD (Liquid Crystal Display) or an organic EL (Electro Luminescence), and displays a video or image according to a video signal or image signal output from the support device 100. The support apparatus 100 includes an R/W (reader/writer) device 106 that detachably mounts an external storage medium 101 and reads and writes programs and/or data to the mounted storage medium 101 .

The communication controller 107 controls communication with external devices (including the PLC 200) via a network. The communication controller 107 includes, for example, a NIC (Network Interface Card). The I/O interface 108 controls data exchange between the CPU 102 and the keyboard 109 and display 110.

HDD305 stores a system program 120 including an OS, a UPG generation program 121 for generating a user program 122, the user program 122, connection information 123, and a distributed design program 124.

The UPG generation program 121 includes an editor that edits (generates) the user program 122 in accordance with user operations received from the keyboard 109, a compiler that compiles the edited user program 122, and a builder that converts the user program 122 into an executable format. The builder may also include a compilation function.

The connection information 123 indicates the connection relationships between the devices in the control system 1. Specifically, the connection information 123 indicates the physical wiring between the devices, the length of the wiring, etc. For example, in the configuration shown in FIG. 1, the connection information 123 indicating the connection relationships between the PLCs 200a, 200b, the communication slaves 300a to 300i, and the switch 400 is created in advance and stored in the HDD 105.

The distributed design program 124 provides design support when constructing the control system 1 as a distributed control system.

(C-2. PLC Hardware Configuration)
Fig. 6 is a diagram showing an example of a hardware configuration of a PLC. As shown in Fig. 6, the PLC 200 includes, as main hardware components, a processor 202, a main memory 204, a storage 206, a field network controller 212, a communication controller 213, and a local bus controller 214. These hardware components are electrically connected via an internal bus 218.

The processor 202 corresponds to an arithmetic processing unit, and is composed of a CPU, a GPU (Graphics Processing Unit), etc. Specifically, the processor 202 reads out a program stored in the storage 210, expands it in the main memory 204, and executes it to realize arithmetic processing and various processes according to the control target.

The main memory 204 is composed of a volatile storage device such as a dynamic random access memory (DRAM) or a static random access memory (SRAM). The storage 206 is composed of a non-volatile storage device such as a solid state drive (SSD) or a hard disk drive (HDD).

Storage 206 stores a system program 220 for implementing basic functions, a partial program 222 that is part of a user program 122 created according to the control target, and system setting information 224 that defines a communication schedule and a calculation schedule. Since the system program 220 implements basic functions in PLC 200, it can be considered as at least a part of the control program.

The field network controller 212 is connected to a network configured to circulate frames. More specifically, the field network controller 212 has a port that handles frame transmission and reception processing using a communication protocol such as EtherCAT (registered trademark) or EtherNet/IP. The field network controller 212 functions as a communication master. The field network controller 212 may also have a synchronization counter for periodically transmitting and receiving frames.

The communication controller 213 controls communication with external devices (including the support device 100) via the network.

The local bus controller 214 is electrically connected to one or more expansion units 216 via an internal bus 218. The expansion unit 216 includes a function for exchanging various signals with the control object. The expansion unit 216 has one or more functions, for example, a DI (Digital Input) function for receiving a digital signal from the control object, a DO (Digital Output) function for outputting a digital signal to the control object, an AI (Analog Input) function for receiving an analog signal from the control object, and an AO (Analog Output) function for outputting an analog signal to the control object. Furthermore, the expansion unit 216 may include a controller that implements special functions such as PID (Proportional Integral Derivative) control and motion control.

Although FIG. 6 shows an example of a configuration in which the necessary functions are provided by the processor 202 executing a program, some or all of these provided functions may be implemented using a dedicated hardware circuit (e.g., an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array)). Alternatively, the main part of the PLC 200 may be realized using hardware that follows a general-purpose architecture (e.g., an industrial PC based on a general-purpose PC). In this case, virtualization technology may be used to run multiple OSs (operating systems) with different uses in parallel, and necessary applications may be executed on each OS.

D. Functional configuration of the support device
Fig. 7 is a diagram showing an example of the functional configuration of the support device. As shown in Fig. 7, the support device 100 includes a storage unit 10, a division unit 11, a scheduling unit 12, a calculation unit 13, a selection unit 14, and a setting unit 15. The storage unit 10 is realized by the ROM 103, the RAM 104, and the HDD 105 shown in Fig. 4. The division unit 11, the scheduling unit 12, the calculation unit 13, the selection unit 14, and the setting unit 15 are realized by the CPU 102 executing the distributed design program 124.

The memory unit 10 stores a user program 122, connection information 123, and a variable list 125.

Figure 8 is a diagram showing an example of a variable list. As shown in Figure 8, the variable list 125 is a list of the device name, the variable name used by the communication slave 300, and the global variable name for each communication slave 300. The variable list 125 is created in advance using the setting environment provided by the support device 100.

The division unit 11 (see FIG. 6) divides the user program 122 into a plurality of partial programs 222. The method of dividing the user program 122 into a plurality of partial programs 222 will be described later.

The scheduling unit 12 identifies multiple combinations for allocating multiple partial programs to multiple PLCs 200 included in the control system 1. The scheduling unit 12 can recognize the number of PLCs 200 included in the control system 1 by referring to the connection information 123. For each of the multiple combinations, the scheduling unit 12 determines a communication schedule for each PLC 200 and a calculation schedule for the processor 202 of each PLC 200 using the connection information and the allocated partial programs.

The calculation unit 13 calculates an evaluation value for each of the multiple combinations according to the communication schedule and the calculation schedule.

The selection unit 14 selects one combination from among the multiple combinations based on the evaluation value. For example, the selection unit 14 displays the evaluation value of each of the multiple combinations on the display 110 and selects one combination in response to an input to the keyboard 109. Alternatively, the selection unit 14 may select one combination with the highest evaluation value from among the multiple combinations.

The setting unit 15 sets the partial program 222 assigned in the selected combination to each of the multiple PLCs 200. Specifically, the setting unit 15 installs the partial program 222 in the PLC 200. Furthermore, the setting unit 15 sets a communication schedule and a calculation schedule corresponding to the selected combination to each of the multiple PLCs 200. Specifically, the setting unit 15 generates system setting information 224 for defining the communication schedule and the calculation schedule for each PLC 200, and sets the generated system setting information 224.

<E. How to divide a user program>
Each of the multiple communication slaves 300 included in the control system 1 is associated with one of multiple mechanisms installed in the production line. Therefore, the multiple communication slaves 300 can be classified into multiple modules according to the associated mechanism.

Figure 9 is a diagram showing an example of modules included in the control system shown in Figure 1. As shown in Figure 9, the control system 1 includes a module Md consisting of mutually related communication slaves 300b to 300d, and a module Me consisting of mutually related communication slaves 300e to 300i.

The division unit 11, for example, divides the user program 122 into multiple partial programs 222 on a module basis.

Figure 10 is a diagram showing an example of an operation definition. Definition 50 shown in Figure 9 defines inputs "A_in1" to "A_inN", logic, and outputs "A_out1" to "A_outM". The logic defines an operation for outputting "A_out1" to "A_outM" by referencing "A_in1" to "A_inN".

The user creates a user program 122 using multiple definitions including the definition 50 shown in FIG. 10. For example, the user creates a user program 122 including the calculation of definition 50 by setting variables or devices to be assigned to the inputs "A_in1" to "A_inN" of definition 50 and variables or devices to be assigned to the outputs "A_out1" to "A_outM" of definition 50.

Figure 11 is a diagram showing an example of a calculation block incorporated in a user program. The calculation block 52 shown in Figure 10 is created by assigning variables or devices to the inputs and outputs of the definition 50 shown in Figure 9. For example, a sensor 60 is assigned to the input "A_in1", a variable 61 is assigned to the input "A_inN", an actuator 62 is assigned to the output "A_out1", and a variable 63 is assigned to the output "A_outM". In this case, the calculation block 52 performs a calculation using the data input from the sensor 60 and the variable 61, outputs the data obtained by the calculation to the actuator 62, and updates the variable 63.

The operation block 52 is created based on the definition 50 and the allocation information. The allocation information indicates the variables or devices to be allocated to each input and the variables or devices to be allocated to each output. The allocation information is created in response to user input when creating the user program 122.

Figure 12 shows a portion of a user program created according to operation definitions and allocation information. As shown in Figure 12, the design information for designing user program 122 includes operation definitions 50 and 51 and allocation information 70 to 72.

The calculation block 52 is created based on the definition 50 and the allocation information 70. The calculation block 52 performs calculations using data input from the sensor 60 and the variables 61, outputs the data obtained by the calculation to the actuator 62, and updates the variables 63.

The calculation block 53 is created based on the definition 50 and the allocation information 71. The calculation block 53 performs calculations using data input from the sensor 64 and the variables 65, outputs the data obtained by the calculation to the actuator 66, and updates the variables 67.

Calculation block 54 is created based on definition 51 and allocation information 72. Calculation block 54 performs calculations using data input from device 80 on the network and variables 63 and 67, outputs the data obtained by the calculation to device 80, and updates variables 61 and 65.

The dividing unit 11 identifies a mechanism including the sensors 60, 64 and the actuators 62, 66, and divides the user program 122 into a plurality of partial programs 222 according to the identification result. The dividing unit 11 may identify a mechanism including the sensors 60, 64 and the actuators 62, 66 according to an input to the keyboard 109. Alternatively, when the connection information 123 includes information indicating the connection relationship between the sensors 60, 64 and the actuators 62, 66 and the mechanism, the dividing unit 11 may refer to the connection information 123 to identify a mechanism including the sensors 60, 64 and the actuators 62, 66.

Figure 13 is a diagram showing an example of dividing a user program into multiple partial programs. As shown in Figure 13, the sensor 60 and the actuator 62 are included in the mechanism 90 associated with the module Md shown in Figure 9. The sensor 64 and the actuator 66 are included in the mechanism 91 associated with the module Me shown in Figure 9.

For each mechanism, the division unit 11 identifies an arithmetic block that performs calculations using input from a device (sensor, actuator, etc.) included in the mechanism, and an arithmetic block that outputs data to the device (sensor, actuator, etc.). For each mechanism, the division unit 11 determines the identified arithmetic block as part of a partial program for a module related to the mechanism.

In the example shown in FIG. 12, the division unit 11 determines an operation block 52 that performs an operation using an input from a sensor 60 included in the mechanism 90 as part of a partial program 222d for a module Md (see FIG. 9) associated with the mechanism 90. Similarly, the division unit 11 determines an operation block 53 that performs an operation using an input from a sensor 64 included in the mechanism 91 as part of a partial program 222e for a module Me (see FIG. 9) associated with the mechanism 91.

Furthermore, for each of the remaining operation blocks, the division unit 11 identifies other operation blocks that update the input variables. If the identified other operation blocks belong to any of the partial programs 222, the division unit 11 includes the remaining operation blocks in the partial program 222 to which the other operation blocks belong. Note that, if there are multiple identified other operation blocks, the division unit 11 selects one operation block from the multiple other operation blocks. The division unit 11 may select one operation block arbitrarily, or may select one operation block in response to an input to the keyboard 109.

Alternatively, the division unit 11 may refer to the variable list 125 to identify a communication slave 300 that updates the variables input to each operation block, and include the operation block in the partial program 222 for the module that includes the identified communication slave 300.

In the example shown in FIG. 13, the division unit 11 identifies an operation block 52 that updates a variable 63 input to an operation block 54. The division unit 11 includes the operation block 54 in the partial program 222d to which the operation block 52 belongs. Alternatively, the division unit 11 may identify an operation block 53 that updates a variable 67 input to an operation block 54. In this case, the division unit 11 includes the operation block 54 in the partial program 222e to which the operation block 53 belongs.

In this way, the division unit 11 divides the user program 122 into multiple partial programs 222.

Figure 14 is a diagram showing an example of partial programs divided from a user program. As shown in Figure 14, the user program 122 is divided into partial program 222d for module Md and partial program 222e for module Me. As shown in Figure 13, the operation block 54 belonging to partial program 222d performs an operation using a variable 67 updated by the operation block 53 belonging to partial program 222e. The operation block 53 performs an operation using a variable 65 updated by the operation block 54. Therefore, as shown in Figure 14, it is necessary to exchange instructions and status between the partial programs 222d and 222e.

<F. Combination of allocating multiple partial programs to multiple PLCs>
The scheduling unit 12 identifies a plurality of combinations for allocating a plurality of partial programs 222 to a plurality of PLCs 200 included in the control system 1. For example, when the control system 1 includes the PLCs 200a and 200b (see FIG. 1) and the user program 122 is divided into partial programs 222d and 222e (see FIG. 13), the scheduling unit 12 identifies the following four combinations (1) to (4).
Combination (1): The partial programs 222d and 222e are assigned to the PLC 200a.
Combination (2): The partial program 222d is assigned to the PLC 200a, and the partial program 222e is assigned to the PLC 200b.
Combination (3): The partial program 222d is assigned to the PLC 200b, and the partial program 222e is assigned to the PLC 200a.
Combination (4): The partial programs 222d and 222e are assigned to the PLC 200b.

Figure 15 is a diagram showing one of the multiple combinations identified by the scheduling unit. Figure 15 shows the above combination (2).

G. Determination of communication schedule and computation schedule
Next, an example of a method for determining a communication schedule and a calculation schedule for each combination will be described with reference to FIGS.

Figure 16 is a diagram showing an example of communication carried out in a control system. Figure 16 shows communication carried out in combination (2) shown in Figure 15. The arrows in the diagram represent communication between devices.

The scheduling unit 12 determines that communication of input/output data (IO data) is required between the PLC 200a and the communication slaves 300b to 300d included in module Md because the partial program 222d assigned to the PLC 200a is intended for module Md. Similarly, the scheduling unit 12 determines that communication of IO data is required between the PLC 200b and the communication slaves 300e to 300i included in module Me because the partial program 222e assigned to the PLC 200b is intended for module Me.

Furthermore, the scheduling unit 12 determines that communication of IO data is required between the communication slave 300a, which is daisy-chain connected to the communication slaves 300b to 300d, and the PLC 200a.

As described above, it is necessary to exchange instructions and status between partial programs 222d and 222e. Therefore, the scheduling unit 12 determines that it is necessary to communicate instructions and status between PLCs 200a and 200b.

The scheduling unit 12 determines the communication schedule when communication is performed using TSN technology. With TSN technology, the time for opening and closing the queue is calculated, the time built into all switches is synchronized, and the time for opening and closing the port is set in all switches based on that time, allowing frames to pass through the switch without waiting in the queue.

Figure 17 is a diagram showing frame communication performed in combination (2) shown in Figure 15. Figure 17 shows how frames are transmitted from PLC 200a to switch 400, PLC 200b, and communication slaves 300b to 300d.

The scheduling unit 12 calculates the time required for frame communication using the frame size, frame propagation time, and delay time for processing within the device.

For example, the opening and closing times of a queue in a port of the switch 400 are calculated as follows: The scheduling unit 12 calculates the opening time of the switch 400 according to formula (a).
Start time=frame transmission start time+offset time+transmission jitter T12+frame propagation delay time T13+frame sending time T11...formula (a).

The frame transmission start time is the time when PLC 200a starts transmitting a frame. The scheduling unit 12 determines the frame transmission start time by analyzing the partial program 222d assigned to PLC 200a in combination (2). The frame transmission start time is determined by setting the time of communication start (steps S7a and S7b) shown in FIG. 4 as 0.

The offset time is the time difference between the internal timer of PLC 200a and the internal timer of switch 400. When determining the communication schedule for each combination, the offset time should be set to 0.

The transmission jitter T12 is the time it takes for a frame to propagate through a communication cable. The scheduling unit 12 stores the transmission jitter T12 measured in advance. Alternatively, if the connection information 123 includes the length of the wiring between the devices, the scheduling unit 12 may refer to the connection information 123 and calculate the transmission jitter T12 by multiplying the length of the wiring by a predetermined coefficient.

The frame propagation delay time T13 is the time required for processing within the switch 400. The scheduling unit 12 stores the frame propagation delay time T13 measured in advance. Alternatively, the scheduling unit 12 stores the frame propagation delay time T13 provided by the vendor selling the switch 400.

The frame transmission time T11 is the time required to transmit a frame from the beginning to the end. The scheduling unit 12 calculates the frame transmission time T11 based on the frame size. The frame size is the size of the IO data to be communicated, and is specified, for example, by the user.

Furthermore, when the size of each frame is the same, the scheduling unit 12 calculates the closing time of the switch 400 according to equation (b), where N is the number of frames to be transmitted consecutively.
Close time=open time+transmission jitter T12×N+frame propagation delay time T13×(N−1)+frame sending time T11×N...equation (b).

In this way, the scheduling unit 12 calculates the open time and close time of the switch 400, and calculates the time T15 during which the switch 400 communicates. In a similar manner, the scheduling unit 12 calculates the time T14 during which the PLC 200a communicates.

Figure 18 is a diagram showing an example of a communication schedule for IO data in a PLC. Figure 18 shows communication processes 41 and 42 for IO data in PLC 200a in combination (2) shown in Figure 15. Communication process 41 is performed between PLC 200a and communication slaves 300b to 300d. Communication process 42 is performed between PLC 200a and PLC 200b. Scheduling unit 12 determines the times for communication processes 41 and 42 by performing the above calculations.

Furthermore, the scheduling unit 12 determines the calculation schedule of the processor 202 of each PLC.

Figure 19 is a diagram showing an example of the allocation of various programs included in a user program to tasks. The user program 122 includes various programs, and each program is assigned to one of multiple tasks according to its priority. The allocation of each program to a task is set according to user input. The multiple tasks include a high-priority primary task, a secondary task with a lower priority than the primary task, and an event task. The primary task is executed at every control period Tc (=X ms) set by the user. The secondary task is executed at every period (=Y ms) set by the user. The length of the period of the secondary task may be the same as the control period Tc, or may be a multiple of the control period Tc. The event task is executed when an event occurs.

In the example shown in FIG. 19, the user program 122 includes a control program 131, a safety program 132, a monitoring program 133, and an event program 134. The control program 131 defines the calculations for controlling the control target. The safety program 132 provides safety functions to prevent human safety from being threatened by equipment, machinery, etc. The monitoring program 133 monitors variables used in the control system 1. The event program 134 defines the operation when an event occurs.

It is desirable for the control program 131 and the safety program 132 to be executed periodically without delay. For this reason, the control program 131 and the safety program 132 are usually assigned to the primary task. In addition, the communication processing of the IO data required for the execution of the control program 131 and the safety program 132 is also assigned to the primary task.

It is desirable for the monitoring program 133 to be executed periodically, but delays are acceptable. For this reason, the monitoring program 133 is usually assigned to a secondary task. The communication processing of IO data required for the execution of the monitoring program 133 is also assigned to a secondary task.

The event program 134 is assigned to an event task because it does not need to be executed periodically.

In TSN technology, a QoS (Quality of Service) priority is set for each frame. Each frame is assigned to a queue according to its QoS priority. QoS priority is set to one of eight values, from "0" to "7." QoS priority "7" is the highest, and QoS priority "0" is the lowest.

It is preferable that frames of IO data required for the execution of the control program 131 and the safety program 132 are communicated with priority. Therefore, a QoS priority of "7" is set for frames of IO data required for the execution of the control program 131 and the safety program 132.

For each PLC 200, the scheduling unit 12 determines the calculation schedule of the processor 202 of the PLC 200 based on the tasks assigned to the partial programs 222 assigned to the PLC 200 and the calculation contents defined by the partial programs 222.

Figure 20 is a diagram showing an example of a schedule determined by the scheduling unit. Figure 20 shows a schedule for processor 202 of PLC 200a in combination (2) shown in Figure 15.

As shown in FIG. 20, the scheduling unit 12 determines, as the schedule for the primary task, a communication schedule for executing communication processes 41 and 42, and a computation schedule for executing computation process 43.

Communication processes 41 and 42 are communication processes for IO data required to execute the program assigned to the primary task in partial program 222d. Communication process 41 is communication process between communication slaves 300b to 300c. Communication process 42 is communication process with PLC 200b. A QoS priority of "7" is set for frames communicated by communication processes 41 and 42.

Calculation process 43 is defined by the program assigned to the primary task in partial program 222d.

Similarly, the scheduling unit 12 determines a communication schedule for executing the communication process 44 as a schedule for the secondary task.

Communication process 44 is a communication process for IO data required for executing a program assigned to a secondary task in partial program 222d. A QoS priority of "5" is set for frames communicated by communication process 44.

The method for calculating the time required for communication processes 41, 42, and 44 is as described with reference to Figures 17 and 18.

The scheduling unit 12 calculates the time required for the calculation process 43 based on the analysis results of the partial program 222d, the user's input information, the operation information of each device, etc.

During free time in the control cycle Tc, for example, calculation processing defined by a program assigned to the event task and other communication processing are executed.

In addition, during the control period Tc other than the time occupied by the communication processes 41, 42, and 44, frames including data that has become necessary due to the results of calculations, data that has become necessary due to the occurrence of an event, etc. are communicated. QoS priorities are set in advance for these frames.

Figure 21 is a diagram showing another example of the allocation of various programs included in a user program to tasks. In the example shown in Figure 21, the user program 122 includes a control program 131, a safety program 132, a monitoring program 133, an event program 134, and a data link setting program 135.

The data link setting program 135 is a program that sets up a data link that automatically updates each other's memory areas using communication between multiple PLCs 200 and always reflects the memory status of one PLC 200 in another PLC 200. By executing the data link setting program 135, the multiple PLCs 200 communicate data in their memory areas with each other.

In the example shown in FIG. 21, the data link setting program 135 is assigned to a secondary task.

Figure 22 is a diagram showing another example of a schedule determined by the scheduling unit. Figure 22 shows a schedule for the processor 202 of PLC 200a in the combination (2) shown in Figure 15. As shown in Figure 22, the scheduling unit 12 includes a communication process 45 for a data link with PLC 200b in the communication schedule of the secondary task. The time required for the communication process 45 is calculated according to the capacity of the memory area.

In this way, the scheduling unit 12 determines the communication schedule and calculation schedule of each PLC 200 for each combination.

Figure 23 shows the schedule for PLC 200a when combination (1) is used to assign partial programs 222d and 222e to PLC 200a.

As shown in FIG. 23, the schedule of PLC 200a includes a communication schedule for executing communication process 41a with all communication slaves 300, and a calculation schedule for executing calculation processes 43d and 43e. Calculation process 43d is defined by partial program 222d for module Md. Calculation process 43e is defined by partial program 222e for module Me.

Figure 24 shows the schedules for PLCs 200a and 200b when combination (2) is used, in which partial programs 222d and 222e are assigned to PLCs 200a and 200b, respectively.

As shown in FIG. 24, the schedule of PLC 200a includes a communication schedule for executing communication processes 41b and 42a, and a calculation schedule for executing calculation process 43d. Communication process 41b is a communication process with communication slaves 300a to 300d (see FIG. 16). Communication process 42a is a communication process with PLC 200b.

The schedule of PLC 200b includes a communication schedule for executing communication processes 41c and 42b, and a calculation schedule for executing calculation process 43e. Communication process 41c is a communication process with communication slaves 300e to 300i (see FIG. 15). Communication process 42b is a communication process with PLC 200a.

Data transmitted from PLC 200a in communication process 42a is received by PLC 200b in communication process 42b. Data transmitted from PLC 200b in communication process 42b is received by PLC 200a in communication process 42a. Therefore, the scheduling unit 12 may operate as an adjustment means for adjusting the time difference Td between the start timing of the control period Tc in PLC 200a and the start timing of the control period Tc in PLC 200b. That is, the scheduling unit 12 adjusts the time difference Td according to the communication timing between PLC 200a and 200b (i.e., the timing of communication processes 42a and 42b). If the time difference Td is uniformly set to 0, unnecessary waiting time occurs between communication process 41c and communication process 42b in PLC 200b. However, by adjusting the time difference Td, the occurrence of such waiting time is suppressed.

<H. Evaluation value calculation method>
A method of calculating an evaluation value according to a communication schedule and a computation schedule will be described with reference to FIGS.

Figure 25 is a diagram showing an example of an evaluation value calculated from a communication schedule and a calculation schedule. As shown in Figure 25, the calculation unit 13 calculates the load rate of the processor 202 of each PLC 200 for each combination as an evaluation value. The calculation unit 13 calculates the load rate of the processor 202 by dividing the total time of the communication processing and calculation processing executed in each control period by the control period Tc.

Furthermore, the calculation unit 13 calculates, for each combination, the proportion of communication processing in the load of the processor 202 of each PLC 200 as an evaluation value. The calculation unit 13 calculates the proportion of communication processing in the load of the processor 202 by dividing the total time of communication processing executed in each control period by the control period Tc.

Figure 26 is a diagram showing another example of an evaluation value calculated from a communication schedule and a calculation schedule. As shown in Figure 25, the calculation unit 13 calculates an index representing the network bandwidth for each communication cable as an evaluation value for each combination. The calculation unit 13 may calculate the index representing the network bandwidth based on the connection relationship between the devices indicated by the connection information 123 and the communication volume for each communication cable.

<I. Examples of Processing by the Selection Unit 14 and the Setting Unit 15>
For example, the selection unit 14 displays the evaluation values calculated by the calculation unit 13 for each combination on the display 110, and prompts the user to input an instruction to select one combination from among the multiple combinations. The user may select a desired combination by referring to the displayed evaluation values. The setting unit 15 may set the communication schedule and the calculation schedule determined for the selected combination in the PLC 200.

<J. Another Example of Determining a Communication Schedule>
Fig. 27 is a diagram showing another example of communication performed in a control system. Fig. 27 shows communication performed in the combination (2) shown in Fig. 15. The arrows in the diagram represent communication between devices. In the combination (2), as described above, the partial program 222d for the module Md is assigned to the PLC 200a, and the partial program 222e for the module Me is assigned to the PLC 200a. However, the expansion unit 216b having the cloud broker function is attached to the PLC 200b, and the partial program 222e assigned to the PLC 200b includes the monitoring program 133b.

The monitoring program 133b monitors input data from the communication slaves 300b to 300i and provides the monitoring results to the expansion unit 216b. The expansion unit 216 outputs the provided monitoring results to the cloud system 500.

The input data from the communication slaves 300b to 300d is necessary for the calculation of the partial program 222d for the module Md. Therefore, the output data from the communication slaves 300b to 300d is sent to the PLC 200a. However, since the monitoring program 133b has been assigned to the PLC 200b, the PLC 200b also needs to receive the input data from the communication slaves 300b to 300d. Therefore, the scheduling unit 12 changes the communication method for the output data from the communication slaves 300b to 300d from unicast addressed to the PLC 200a to multicast addressed to the PLCs 200a and 200b. This allows the PLCs 200a and 200b to obtain the output data from the communication slaves 300b to 300d.

Figure 28 shows the schedules of PLCs 200a and 200b when partial program 222e includes a monitoring program in combination (2).

The schedule shown in FIG. 28 differs from the schedule shown in FIG. 25 in that the communication schedule of PLC 200b includes communication process 46 and provision process 47. Communication process 46 is a process for reading input data that has been multicast from communication slaves 300b to 300d. In this way, the scheduling unit 12 need only incorporate a read time for reading input data transmitted by multicast into the communication schedule of PLC 200b.

Furthermore, the scheduling unit 12 may operate as an adjustment means for adjusting the time difference Td between the start timing of the control period Tc in PLC 200a and the start timing of the control period Tc in PLC 200b according to the read time. That is, the scheduling unit 12 adjusts the time difference Td so that the communication process 46 is performed after the input data is multicast from the communication slaves 300b to 300d. This reduces the occurrence of unnecessary waiting time.

The provision process 47 is a process that provides input data from the communication slaves 300b to 300i to the expansion unit 216b.

<K. Setting the processing schedule of the communication slave>
The setting unit 15 may set a processing schedule for the communication slave 300 based on the communication schedule for each PLC 200 determined for the combination selected by the selection unit 14 .

Figure 29 is a diagram showing an example of a method for setting the processing schedule of the communication slaves. As shown in Figure 29, the setting unit 15 identifies the latest timing t1 of the timing at which a frame arrives at the multiple communication slaves 300 within the control period Tc based on the communication schedules of each of the PLCs 200a and 200b corresponding to the selected combination. The setting unit 15 sets the timing t2 at which the multiple communication slaves 300 start various processes to be after timing t1. This makes it possible to synchronize the processing of the multiple communication slaves 300.

L.TSN Scheduling
As described above, the PLC 200 having a CNC implemented therein among the plurality of PLCs 200 performs scheduling of the TSN. When the partial program 222 is set in each of the plurality of PLCs 200, the PLC 200 having a CNC implemented therein may adjust the phase of the control period of each PLC 200 using a value actually measured online. That is, the PLC 200 having a CNC implemented therein may operate as an adjustment means for adjusting the time difference Td between the start timing of the control period Tc in the PLC 200a and the start timing of the control period Tc in the PLC 200b. Alternatively, a network controller provided in the control system 1 may operate as an adjustment means for adjusting the time difference Td.

For example, when IO data communication is required between PLC 200a and PLC 200b, PLC 200 equipped with a CNC adjusts the time difference Td according to the communication schedule between PLC 200a and PLC 200b, as shown in FIG. 24.

Alternatively, when PLC 200b needs to read input data transmitted by the multicast method (see FIG. 27), PLC 200 equipped with a CNC adjusts the time difference Td according to the read time of the input data by PLC 200b, as shown in FIG. 28.

§3. Supplementary Note As described above, the disclosure according to the above embodiment includes the following disclosure.

<Configuration 1>
A control system (1) for controlling a control target,
A plurality of communication slaves (300);
A plurality of control devices (200) operating as communication masters;
Each of the plurality of control devices (200) includes a processor (202);
The control system (1) further comprises:
A dividing means (11, 102) for dividing a user program (122) for controlling the control target into a plurality of partial programs (222);
a scheduling means (12, 102) for determining, for each of a plurality of combinations of allocating the plurality of partial programs (222) to the plurality of control devices (200), a communication schedule for each of the plurality of control devices (200) and a calculation schedule for each of the processors (202) of the plurality of control devices (200) using information indicating a connection relationship between the plurality of control devices (200) and the plurality of communication slaves (300) and the allocated partial programs (222);
A control system (1) comprising: a calculation means (13, 102) for calculating an evaluation value according to the communication schedule and the calculation schedule for each of the plurality of combinations.

<Configuration 2>
a selection means (13, 102) for selecting one combination from among the plurality of combinations based on the evaluation value;
The control system (1) according to configuration 1, further comprising: a setting means (14, 102) for setting a partial program (222) assigned in one of the combinations to each of the plurality of control devices (200).

<Configuration 3>
Each of the plurality of control devices (200) executes communication of input/output data with at least one of the plurality of communication slaves (300) and a calculation using the input/output data at each predetermined control period;
The plurality of control devices (200) include a first control device (200a) and a second control device (200b),
The control system (1) further comprises:
The control system (1) according to configuration 1 or 2, further comprising an adjustment means (12, 102, 200) for adjusting a time difference between a start timing of the control cycle in the first control device (200a) and a start timing of the control cycle in the second control device (200b) in accordance with a communication timing between the first control device (200a) and the second control device (200b).

<Configuration 4>
The user program (122) includes a monitoring program (133b) for monitoring input data from the plurality of communication slaves,
The plurality of control devices (200) include a first control device (200a) to which the monitoring program (133b) is not assigned, and a second control device (200b) to which the monitoring program (133b) is assigned,
The scheduling means (12, 102)
A communication method from any one of the plurality of communication slaves (300) to the first control device (200a) is set to a multicast destination designated for the first control device (200a) and the second control device (200b);
3. The control system (1) according to configuration 1 or 2, wherein a read time for reading the input data transmitted by the multicast is incorporated into a communication schedule of the second control device (200b).

<Configuration 5>
Each of the plurality of control devices (200) executes communication of input/output data with at least one of the plurality of communication slaves (300) and a calculation using the input/output data at each predetermined control period;
The control system (1) further comprises:
The control system (1) of configuration 4 further comprises an adjustment means (12, 102, 200) for adjusting a time difference between a start timing of the control cycle in the first control device (200a) and a start timing of the control cycle in the second control device (200b) in accordance with the readout time.

<Configuration 6>
Each of the plurality of control devices (200) transmits output data to at least one of the plurality of communication slaves (300) at each predetermined control period;
The setting means (15, 102) further includes:
identifying a first timing, which is the latest among timings at which the output data arrives at the plurality of communication slaves (300) within the control period, based on the communication schedule of each of the plurality of control devices (200) determined for the one combination;
The control system (1) according to configuration 2, wherein a second timing at which the plurality of communication slaves (300) start processing is set to be later than or equal to the first timing.

<Configuration 7>
A method for supporting a control system (1) for controlling a controlled object, comprising:
The control system (1)
A plurality of communication slaves (300);
A plurality of control devices (200) operating as communication masters;
Each of the plurality of control devices (200) includes a processor (202);
The support method includes:
Dividing a user program (122) for controlling the control target into a plurality of partial programs (222);
determining, for each of a plurality of combinations of allocating the plurality of partial programs (222) to the plurality of control devices (200), a communication schedule for each of the plurality of control devices (200) and a calculation schedule for each of the processors (202) of the plurality of control devices (200) using information (123) indicating a connection relationship between the plurality of control devices (200) and the plurality of communication slaves (300) and the allocated partial programs (222);
calculating an evaluation value for each of the plurality of combinations according to the communication schedule and the computation schedule.

<Configuration 8>
A program (124) for causing a computer to execute the support method according to configuration 7.

The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. Furthermore, the inventions described in the embodiments and each modified example are intended to be implemented, as far as possible, either alone or in combination.

1, 1X, 1Y, 1Z Control system, 10 Memory unit, 11 Division unit, 12 Scheduling unit, 13 Calculation unit, 14 Selection unit, 15 Setting unit, 41, 41a to 41c, 42, 42a, 42b, 44 to 46 Communication processing, 43, 43d, 43e Calculation processing, 47 Provision processing, 50, 51 Definition, 52 to 54 Calculation block, 60, 64 Sensor, 61, 63, 65, 67 Variable, 62, 66 Actuator, 70 to 72 Allocation information, 80 Equipment, 90, 91 Mechanism, 100 Support device, 101 Storage medium, 102 CPU, 103 ROM, 104 RAM, 106 Device, 107, 213 Communication controller, 108 I/O interface, 109 Keyboard, 110 Display, 120, 220 System program, 121 UPG generation program, 122, 122X, 122Y, 122Z User program, 122Za, 122Zb, 122Zc program, 123 Connection information, 124 Distributed design program, 125 Variable list, 131 Control program, 132 Safety program, 133, 133b Monitoring program, 134 Event program, 135 Data link setting program, 200, 200X, 200Xa, 200Xb, 200Xc, 200Y, 200a, 200b PLC, 202 Processor, 204 Main memory, 206, 210 Storage, 212 Field network controller, 214 Local bus controller, 216, 216b Expansion unit, 218 Internal bus, 222, 222d, 222e Partial program, 224 system setting information, 300, 300a-300i communication slave, 400, 400Z switch, 500 cloud system.

Claims (7)

A control system for controlling a control target,
A plurality of communication slaves;
a plurality of control devices acting as communication masters;
each of the plurality of control devices includes a processor;
The control system further comprises:
A dividing means for dividing a user program for controlling the controlled object into a plurality of partial programs;
a scheduling means for determining, for each of a plurality of combinations of allocating the plurality of partial programs to the plurality of control devices, a communication schedule for each of the plurality of control devices and a calculation schedule for each of the processors of the plurality of control devices, using information indicating a connection relationship between the plurality of control devices and the plurality of communication slaves and the allocated partial programs;
a calculation means for calculating an evaluation value according to the communication schedule and the calculation schedule for each of the plurality of combinations,
the user program includes a monitoring program that monitors input data from the plurality of communication slaves;
the plurality of control devices include a first control device to which the monitoring program is not assigned and a second control device to which the monitoring program is assigned;
The scheduling means comprises:
A communication method from any one of the plurality of communication slaves to the first control device is set to a multicast destination designated to the first control device and the second control device;
A control system incorporating a read time for reading the input data transmitted by the multicast into a communication schedule of the second control device . a selection means for selecting one combination from among the plurality of combinations based on the evaluation value;
The control system according to claim 1 , further comprising: a setting unit that sets a partial program assigned in said one combination to each of said plurality of control devices. each of the plurality of control devices executes communication of input/output data with at least one of the plurality of communication slaves and a calculation using the input/output data at each predetermined control period;
The plurality of control devices includes two control devices,
The control system further comprises:
3. The control system according to claim 1 or 2 , further comprising an adjustment means for adjusting the time difference between the start timing of the control period in one of the two control devices and the start timing of the control period in the other of the two control devices in accordance with communication timing between the two control devices. each of the plurality of control devices executes communication of input/output data with at least one of the plurality of communication slaves and a calculation using the input/output data at each predetermined control period;
The control system further comprises:
3. The control system according to claim 1, further comprising an adjustment means for adjusting a time difference between a start timing of the control cycle in the first control device and a start timing of the control cycle in the second control device in accordance with the readout time. each of the plurality of control devices transmits output data to at least one of the plurality of communication slaves at each predetermined control period;
The setting means further includes:
identifying a first timing, which is the latest among timings at which the output data arrives at the plurality of communication slaves within the control period, based on the communication schedule of each of the plurality of control devices determined for the one combination;
The control system according to claim 2 , wherein a second timing at which the plurality of communication slaves start processing is set to be later than or equal to the first timing. A method for supporting a control system that controls a control target, comprising the steps of:
The control system includes:
A plurality of communication slaves;
a plurality of control devices acting as communication masters;
each of the plurality of control devices includes a processor;
The support method includes:
Dividing a user program for controlling the control target into a plurality of partial programs;
determining, for each of a plurality of combinations of allocating the plurality of partial programs to the plurality of control devices, a communication schedule for each of the plurality of control devices and a calculation schedule for each of the processors of the plurality of control devices, using information indicating a connection relationship between the plurality of control devices and the plurality of communication slaves and the allocated partial programs;
calculating an evaluation value according to the communication schedule and the calculation schedule for each of the plurality of combinations ;
the user program includes a monitoring program that monitors input data from the plurality of communication slaves;
the plurality of control devices include a first control device to which the monitoring program is not assigned and a second control device to which the monitoring program is assigned;
The step of determining the communication schedule includes:
setting a communication method from any one of the plurality of communication slaves to the first control device to a multicast destination designated by the first control device and the second control device;
incorporating in a communication schedule of the second control device a read time for reading the input data transmitted by the multicast . A program for causing a computer to execute the support method according to claim 6 .

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