WO2022185589A1 - Information processing device, method, and program - Google Patents

Abstract

The objective of the present invention is to set a communication cycle range that satisfies a synchronization accuracy, from a processing load of a control device and a network load. This information processing device: calculates a first communication cycle for each control device, from a surplus time based on a processing load for control-related processing in a pre-determined cycle, and a required time for performing time synchronization processing once; calculates a second communication cycle from a surplus bandwidth based on the network load and a bandwidth required to communicate one synchronization message; and calculates a range for a communication cycle for the synchronization message using the longer cycle from among both the longest cycle among the first communication cycles for each control device and the second communication cycle, and a communication cycle based on a predetermined synchronization accuracy.

Description

Information processing device, method and program

The present disclosure relates to a device that sets the communication cycle of a FA (Factory Automation) control system.

Control systems using control devices such as PLCs (Programmable Logic Controllers) are widely used at various production sites. As a control system, in addition to a system in which a single controller controls peripheral devices, a distributed control system in which a plurality of controllers exchange data with each other and cooperatively control peripheral devices has been proposed. In a distributed control system, it is desired that multiple controllers be time-synchronized with each other in order to cooperate with high accuracy.

For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2016-131332) discloses a configuration that realizes time synchronization while suppressing network bandwidth consumption. Further, Patent Document 2 (Japanese Patent Application Laid-Open No. 2018-88646) discloses a configuration that realizes time synchronization by reducing traffic.

JP 2016-131332 A JP 2018-88646 A

Even if the required synchronization accuracy can be met in the FA control system, the processing load and the network load will increase, and there is a possibility that the accuracy of distributed control cannot be ensured. More specifically, when the control processing load is high in each control device during the control cycle, the control processing cannot be completed within the control cycle. In addition, a communication band must be secured in the network for communication between the control devices, but if the network band is squeezed by the communication for time synchronization, it becomes difficult to secure the communication band.

Therefore, the shorter the communication cycle for time synchronization, the better the synchronization accuracy, but the higher the load related to time synchronization processing or the load related to the network. There is a so-called trade-off relationship with high-precision synchronization, and an appropriate communication cycle setting process is desired.

An information processing device according to the present disclosure is an information processing device that processes communication cycles of a plurality of control devices connected to a FA (factory automation) network, and each of the plurality of control devices has a control-related and a time synchronization process for synchronizing the time between the control devices according to the synchronization message, and the information processing device calculates the range of the cycle for communicating the synchronization message to each control device via the network. A range calculation unit is provided, and the range calculation unit calculates, for each control device, the margin time excluding the execution time of the processing based on the processing load of the control-related processing in a predetermined cycle, and the one time executed by the control device A first calculation unit that calculates a first communication cycle from the time required for time synchronization processing, a surplus bandwidth obtained by removing the bandwidth based on the network load from the available bandwidth of the network, and one synchronization message communication and a second calculation unit that calculates a second communication cycle from the bandwidth required for each control device, and which of the longest cycle of the first communication cycles and the second communication cycle of each control device is the longest The range is calculated using the one communication cycle and the communication cycle based on the predetermined synchronization accuracy.

According to the above disclosure, in a configuration in which a plurality of control devices that perform time synchronization processing between control devices according to a synchronization message are connected to a network, the information processing device is based on the processing load of each control device and the communication load of the network. From the communication cycle and the communication cycle based on the predetermined synchronization accuracy, it is possible to calculate the range in which the cycle for communicating the synchronization message to each control device via the network should be set.

In the above disclosure, the range calculation unit calculates the communication cycle and the longer cycle based on predetermined synchronization accuracy as the upper limit value and the lower limit value of the range, respectively.

According to the above disclosure, the information processing device sets the range to be equal to or more than the communication cycle based on the processing load of each control device and the communication load of the network and equal to or less than the communication cycle based on the predetermined synchronization accuracy. calculate.

In the above disclosure, the information processing device includes a range display unit that displays the range of cycles calculated by the range calculation unit on a display, and a range of the calculated cycles based on a user operation on the information processing device. A determination unit that determines a period for communicating the message to each control device via the network.

According to the above disclosure, the user can selectively determine the cycle for communicating the synchronization message to each control device via the network from the communication cycle range calculated and displayed by the information processing device.

In the above disclosure, the range display unit causes the display to display the default cycle according to the communication protocol applied to the network in association with the range.

In the above disclosure, it is possible to selectively determine the period for communicating with each control device via the network, using the default period displayed in association with the range as a guide.

In the above disclosure, data indicating the cycle determined by the determination unit is set in each control device.

According to the above disclosure, when the communication cycle is determined based on the user's operation, the information processing device can automatically set the determined communication cycle to each control device.

In the above disclosure, the information processing device further includes an evaluation unit that evaluates synchronization accuracy when each control device executes time synchronization processing according to a synchronization message transmitted based on the determined cycle.

According to the above disclosure, the user can use the evaluated synchronization accuracy as support information for judging the validity of the period determined by the user.

In the above disclosure, the first calculation unit calculates the margin time and the required time from the first information, and the first information is a predetermined period, the processing performance of each control device, and the control-related The second calculation unit calculates the available bandwidth, the bandwidth based on the network load, and the bandwidth required for communication of one synchronization message from the second information. , the second information includes items of network transmission performance, bandwidth required for processing by each control device, and time synchronization performance of each control device, and the information processing device further includes items of the first information, A UI (user interface) for displaying items of the second information and items of predetermined synchronization accuracy and accepting a user operation for adjusting at least one item is provided.

According to the above disclosure, the user can check the items for calculating the first communication cycle and the second communication cycle for determining the range and the synchronization accuracy, and can operate and adjust these items. .

In the above disclosure, the UI further displays one or more change modes for changing the calculated range, items to be adjusted in association with each change mode, and adjustment amounts.

According to the above disclosure, when a user operates and adjusts an item, as information supporting the adjustment operation, for each change mode of the calculated range, the item to be adjusted to realize the change mode is The amount of adjustment can be obtained.

In the above disclosure, the UI further calculates a communication cycle range based on the first information, the second information, and the predetermined synchronization accuracy when an adjustment operation is received from the user. start the department.

According to the above disclosure, the information processing device calculates the range based on the item adjusted by the user's operation, so the user can determine the appropriateness of the adjustment amount of the item from the calculated range.

In the above disclosure, the plurality of control devices constitute a distributed control system provided for each different FA process.

According to the above disclosure, for a distributed control system, it is possible to calculate the range of communication cycles of synchronization messages for time synchronization with a predetermined synchronization accuracy between control devices provided in different processes.

In the above disclosure, the control device connects one or more devices to be controlled, and the predetermined cycle indicates the control cycle.

According to the above disclosure, the range of communication cycles of synchronization messages for time synchronization can be set using control cycles.

A method according to the present disclosure is a method of processing communication cycles of a plurality of control devices connected to a FA (factory automation) network, wherein each of the plurality of control devices performs control-related processing and synchronization An execution unit that executes processing including time synchronization processing for synchronizing time between control devices according to the message, and the method includes calculating a period range for communicating a synchronization message to each control device via a network. In the step of calculating the range, for each control device, the margin time excluding the execution time of the processing based on the processing load of the control-related processing in a predetermined cycle and the time of one execution by the control device A step of calculating a first communication cycle from the time required for synchronization processing, a surplus bandwidth obtained by removing a bandwidth based on the network load from the available bandwidth of the network, and a bandwidth required for communication of one synchronization message. a step of calculating a second communication cycle from, a longer communication cycle of both the longest cycle and the second communication cycle of the first communication cycles of each control device, and a predetermined synchronization and calculating the range using the accuracy-based communication period.

According to the method disclosed above, in a configuration in which a plurality of control devices that perform time synchronization processing among control devices according to a synchronization message are connected to a network, the communication cycle is based on the processing load of each control device and the communication load of the network. and the communication cycle based on the predetermined synchronization accuracy, the range in which the cycle of communicating the synchronization message to each control device via the network should be set can be calculated.

According to the present disclosure, there is provided a program for causing a processor to execute the method described above. When the program is executed by the processor, a synchronization message is sent to each control device via the network based on the communication cycle based on the processing load of each control device and the communication load on the network, and the communication cycle based on the predetermined synchronization accuracy. The range in which the communication period should be set can be calculated.

According to the present disclosure, it is possible to set a period range for time synchronization that satisfies the synchronization accuracy based on the processing load of the control device and the network load.

It is a figure showing typically an example of the whole composition of control system 1 concerning this embodiment. It is a schematic diagram which shows the structural example regarding the time synchronization which concerns on this Embodiment. 3 is a diagram for explaining data communication of distributed system 300 according to the present embodiment. FIG. 2 is a block diagram showing a hardware configuration example of a control device 2 according to this embodiment; FIG. 2 is a block diagram showing a hardware configuration example of a support device 500 according to this embodiment; FIG. 2 is a block diagram showing a software configuration example of a control device 2 according to the embodiment; FIG. 5 is a diagram schematically showing a module configuration of support device 500 according to the present embodiment; FIG. 5 is a flowchart showing a schematic process of communication cycle setting according to the present embodiment; It is a figure which shows an example of the calculation process of the 1st communication period based on the processing load which concerns on this Embodiment. FIG. 9 is a diagram showing an example of calculation processing of a second communication cycle based on network load according to the present embodiment; FIG. 10 is a diagram showing a data flow in setting a range of communication cycles according to the present embodiment; 5 is a graph schematically showing the relationship between synchronization accuracy and the number of nodes; FIG. 5 is a diagram showing an example of a UI screen for communication cycle setting according to the present embodiment; FIG. 10 is a diagram showing another example of a UI screen for communication cycle setting according to the present embodiment; FIG. 10 is a diagram showing an example of a UI screen for adjusting setting conditions of a periodic range according to the embodiment; FIG. 3 is a diagram showing an example of a PTP communication sequence;

Embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated.

<A. Application example>
First, an example of a scene to which the present invention is applied will be described. In the present embodiment, a PLC will be described as a typical example of a "control device", but the technical ideas disclosed in this specification can be applied to any control device without being limited to the name of the PLC. It is possible.

Also, in this embodiment, the control device has a management timer that manages time. The control device executes a "time synchronization process" for matching the management timer with the reference timer that manages the reference time.

FIG. 1 is a diagram schematically showing an example of the overall configuration of a control system 1 according to this embodiment.

　With reference to Fig. 1, the control system 1 realizes the FA of the production line. More specifically, in the control system 1, networks are connected at multiple levels, and different functions are assigned to the networks at each level. Specifically, but not exclusively, for example, four levels of networks 11-14 are provided.

The network 11 is a control level network. The network 11 connects a plurality of control devices 2A, 2B and 2C, a device/line management device 190, and a display device 280 that provides a SCADA (Supervisory Control And Data Acquisition) function. A data link is formed through which data can be exchanged. The controllers 2A, 2B and 2C are referred to as "controller 2" when not distinguished. The network 11 mainly transmits information related to time synchronization and control systems.

One or more field devices 90 are connected to the control device 2 . These field devices 90 may be directly connected to the control device 2 or may be connected to the control device 2 via the network 110 . Each of the one or more field devices 90 exchanges information between an actuator that exerts some physical action on a manufacturing device or a production line (hereinafter also collectively referred to as "field") and the field. Including input/output devices. Thus, the control system 1 shown in FIG. 1 has a field level network 110 in addition to the four levels of networks 11-14.

The data exchanged between the control device 2 and the field device 90 via the network 110 is updated in a very short cycle of several hundred microseconds to several tens of milliseconds. Note that such update processing of exchanged data is also called input/output refresh processing.

The network 12 is provided as a management level network. Connected to the network 12 are a device/line management device 190 for managing devices and lines, and manufacturing management devices 380 and 390 for managing manufacturing plans and the like. The equipment/line management device 190 and the manufacturing management equipments 380 and 390 exchange management information such as manufacturing plans and equipment or line information via the network 12 .

The network 13 is provided as a computer-level network. Connected to the network 13 are manufacturing control devices 380 and 390 and a manufacturing execution system (MES) 400 that manages a time series DB (abbreviation for database) 450 . Manufacturing control devices 380 and 390 and manufacturing execution system 400 exchange production control and information system data via network 13 .

The manufacturing execution system 400 stores observed values, which are input values from the field devices 90 collected via the network 13, in the time-series DB 450 as time-series data according to the observed order. Specifically, in the present embodiment, control device 2 generates a frame containing a specified observation value and the time of the management timer, and transfers the frame to manufacturing execution system 400 via networks 11 , 12 and 13 .

The network 14 includes external networks such as the Internet. The manufacturing execution system 400 and external devices on the cloud are connected to the network 14 . The manufacturing execution system 400 transfers the data of the time-series DB 450 to the device on the cloud by exchanging data with the device on the cloud.

In the control system 1 shown in FIG. 1, the networks 11 to 14 and the network 110 adopt protocols and frameworks corresponding to such differences in required characteristics. For example, as the protocol of the networks 11 and 12 belonging to the factory network, EtherNet/IP (registered trademark), which is an industrial open network in which a control protocol is implemented on general-purpose Ethernet (registered trademark), may be used. As a protocol for the network 110, EtherCAT (registered trademark), which is an example of a machine control network, may be adopted. Note that the protocol of the network 11 and the protocol of the network 110 may be the same or different. By adopting network technology suitable for such machine control, it is possible to provide real-time performance in which the time required for transmission between devices is guaranteed.

On the other hand, as a protocol for the networks 13 and 14 belonging to the corporate network, general-purpose Ethernet or the like is used in order to ensure the diversity of connection destinations. By adopting general-purpose Ethernet, restrictions such as the amount of data that can be transmitted can be eliminated.

A support device 500 can be connected to the control device 2 or the device/line management device 190 . The support device 500 is a device that assists preparations necessary for the control device 2 to control the controlled object.

The control system 1 comprises a distributed system 300 in which controllers 2A, 2B and 2C are provided in different processes 3A, 3B and 3C, respectively. Although not limited, for example, step 3A indicates a step of a parts feeder that conveys works (parts, members) while aligning them, and step 3B indicates a step of moving the works aligned in step 3A by the Pick & Place operation of the robot. , and step 3C shows the step of assembling the work after movement. In the distributed system 300, the operation of the field device 90 connected to the control device 2 of each process is different from the operation of the field device 90 connected to the control device 2 of the preceding and subsequent processes. In order to satisfy the required takt time in the distributed system 300, the operation in a certain process is performed in synchronization with the operations in the processes before and after that process.

The control device 2 pre-loads a control-related program including a sequence program for realizing sequence control and a motion program for realizing motion control of the field device 90 connected to the control device 2 based on a synchronized time. Real-time control of the field device 90 is realized by executing it at each predetermined cycle (this is also called a control cycle).

In the present disclosure, "time" is intended to indicate a certain point in the flow of time, and is defined using units such as hours, minutes, and seconds. A "timer" measures a value for controlling timing within the control device 2 and related devices, and basically includes a counter that is incremented or decremented by a predetermined value every predetermined unit time. can be configured. The counter has a predetermined bit length representing, for example, an integer value. The “synchronization accuracy” can be indicated based on the time difference (error or displacement) between the reference timer and the management timer of the control device 2 . Therefore, the smaller the time difference (error or displacement), the higher the "synchronization accuracy", and the larger the time difference (error or displacement), the lower the "synchronization accuracy".

The configuration that realizes time synchronization in FIG. 1 is, for example, a case where the network 11 implements data communication according to TSN (Time-Sensitive Networking), which is a protocol for industrial networks, and a case where the network 11 is EtherCAT (registered trademark: Ethernet for Control). and a case of implementing data communication according to Automation Technology). Note that the standards applied to the network 11 are not limited to these, and may be IEEE1588, for example.

Referring to FIG. 1, the master serving as the "reference timer" is a timer possessed by any one of control devices 2A, 2B and 2C, and corresponds to the timer with the highest accuracy among these timers. The master is not limited to the control device 2, but may be a timer of another device on the network 11 (eg device/line management device 190).

The support device 500 provides a support tool that assists the user in setting the communication cycle of synchronization messages for time synchronization when designing the control system 1 (or the distributed system 300).

The support device 500 executes communication cycle setting processing as a support tool. More specifically, the support device 500 calculates the range of communication cycles that can be set (step S5), and presents the calculated range to the user by displaying it (step S7). When the user determines a desired communication cycle within the presented communication cycle range by operating the support device 500, the support device 500 provides a command for setting the communication cycle data 200 indicating the communication cycle determined by the user. A notification is sent to each control device 2 (step S11). Details of the processing in steps S5, S7, and S11 will be described later with reference to FIG.

In step S5, the support device 500 sets the range of cycles for communicating synchronization messages to each control device 2 via the network 11. More specifically, the support device 500 calculates the shortest communication cycle in the cycle range based on the processing load and network load of each control device 2, and sets the longest communication cycle to the system in the specifications, for example. Calculated based on the required synchronization accuracy.

The support device 500 sets the longer one of the first communication cycle based on the processing load of each control device 2 and the second communication cycle based on the network load as the shortest communication cycle. More specifically, the support device 500 defines the first communication cycle as a surplus time excluding the execution time of the processing based on the processing load of processing related to control in a predetermined cycle for each control device 2. and the required time for one time synchronization process executed by the control device 2 . Accordingly, the first communication period may correspond to one or more lengths of the predetermined period. In addition, the support device 500 calculates the second communication cycle from the surplus bandwidth obtained by removing the bandwidth based on the network load from the available bandwidth of the network 11 and the bandwidth required for one synchronization message communication. This network load may include, in addition to the load associated with communication between control devices 2 in network 11, the load associated with communication between control device 2 and a higher-level network (one or more of networks 12, 13 and 14).

The support device 500 selects the longer of both the longest cycle of the first communication cycles calculated for each control device 2 and the second communication cycle as the shortest communication cycle. A communication cycle based on a predetermined synchronization accuracy is set to the longest communication cycle. This predetermined synchronization accuracy includes the synchronization accuracy required for the control system 1 (more specifically, the distributed system 300).

The support device 500 presents the calculated communication cycle range of the synchronization message to the user. The user determines the communication cycle to be set in each control device 2 within the presented communication cycle range, and the support device 500 transmits communication cycle data 200 notifying the determined communication cycle to each control device 2. do.

As a result, the user can set a communication cycle based on the processing load of each control device 2 and the network load, and which satisfies the synchronization accuracy required for the system.

In the present embodiment, "calculating" the load, cycle, range, etc. also includes estimating or estimating the load, cycle, range, etc. The above-mentioned "margin time" corresponds to time during which time synchronization processing can be executed in a predetermined cycle. Also, "required time" indicates the time from the start to the end of processing when resources (such as processors) of the control device 2 that can be used for executing the processing are used only for executing the time synchronization processing. In the distributed system 300, the type of control-related processing executed by the control device 2 (processing program size (number of instructions, number of steps), etc.) and the processing performance of the control device 2 (processor operation speed, memory type, memory (read/write speed, etc.) differ among the control devices 2, so the spare time and the required time also differ among the control devices 2. FIG. Due to such characteristics of the distributed system 300, it is significant to calculate the shortest period using the first communication period based on the processing load of each control device 2. FIG.

Further, in the present embodiment, the available bandwidth of the network 11 is preferentially allocated to control system data related to control-related processing in order to guarantee the data arrival time, and the surplus bandwidth is used in situations such as communication requests. Other data, such as synchronization messages, are allocated accordingly. The size of the surplus band, which is the remaining communication band of the network 11, changes according to the size of the "network load" including the band allocated to the control system data communication of the network 11 and the communication band with the upper network. , the second communication cycle also changes according to the magnitude of the network load. Due to such characteristics of network band allocation, it is significant to calculate the shortest period using the second communication period based on the network load.

A more specific application example of the present embodiment will be described below.
<B. Time Synchronization in Control System 1>
In control system 1 according to the present embodiment, the timers included in each of a plurality of control devices 2 are synchronized with each other. This realizes cooperative control of a plurality of field devices 90 that are connected to different control devices 2, that is, between different processes.

The time synchronization function provided by the control system 1 according to this embodiment will be described below.
(b1. Network configuration example)
FIG. 2 is a schematic diagram showing a configuration example related to time synchronization according to this embodiment. Referring to FIG. 2, a distributed system 300 includes a plurality of control devices 2A, 2B and 2C and a plurality of field devices 90A-90I to be controlled. As an example, the control system 1 employs a network in which at least some of the control devices are daisy chain connected. Each of controllers 2A, 2B and 2C functions as a master managing data transmission within corresponding network 110 . Field devices 90A to 90I function as slaves that perform data transmission according to commands from corresponding masters.

The control devices 2A, 2B and 2C are connected to a control level network 11. Field devices 90A, 90B and 90C are sequentially connected in a daisy chain to the network 110 connected to the control device 2A, and field devices 90D, 90E and 90F are connected in a daisy chain to the network 110 connected to the control device 2B. Field devices 90G, 90H and 90I are sequentially connected in a daisy chain to a network 110 that is sequentially connected in a chain and connected to the control device 2C. The connection form of the field device 90 on the network 110 is not limited to a daisy chain.

Within the network 110, the control device 2 and the one or more field devices 90 can all be regarded as communication devices having a data transmission function. is transmitted to another adjacently connected communication device as needed.

Transmission and reception timings are synchronized between a plurality of communication devices connected to the network 110, that is, the control device 2 and one or more field devices 90 (corresponding to time synchronization (3) in the figure). Specifically, the control device 2 and the one or more field devices 90 each comprise timers that are time-synchronized with each other. Controller 2 and one or more field devices 90 each determine when to transmit or receive data according to their time-synchronized timers. In the present embodiment, "timing" represents the concept of timing, time, or time when some event occurs.

Referring to FIG. 2, control device 2A includes timer 102A, and field devices 90A, 90B and 90C include timers 91A, 91B and 91C, respectively. Timer 102A of controller 2A acts as a master, and timers 91A, 91B and 91C of field devices 90A, 90B and 90C synchronize timing with respect to this master. For example, values based on the timer value of timer 102A are set to timers 91A, 91B and 91C.

The control device 2B has a timer 102B, and the field devices 90D, 90E and 90F have timers 91D, 91E and 91F, respectively. Timer 102B of controller 2B acts as a master, and timers 91D, 91E and 91F of field devices 90D, 90E and 90F synchronize their timing with respect to this master. For example, values based on the timer value of timer 102B are set to timers 91D, 91E and 91F.

The control device 2C has a timer 102C, and the field devices 90G, 90H and 90I have timers 91G, 91H and 91I respectively. Timer 102C of controller 2C acts as a master and timers 91G, 91H and 91I of field devices 90G, 90H and 90I synchronize their timing with respect to this master. For example, timers 91G, 91H and 91I are set to values based on the timer value of timer 102C.

That is, each of the control devices 2A, 2B and 2C functions as a master that manages data transmission within the corresponding network 110, and the field device 90 connected to each control device 2 performs data transmission according to commands from the master. Acts as a slave to perform By synchronizing the timers between the master and the slave, the data transmission timing and the like can be matched between the control device 2 and the field device 90 that constitute the network 110 .

In the example shown in FIG. 2, the control device 2A further has a timer 101A synchronized with the timer 102A. The control device 2B further has a timer 101B time-synchronized with the timer 102B. The control device 2C further has a timer 101C time-synchronized with the timer 102C (corresponding to time synchronization (2) in the figure). In the control system 1, for example, one of the timers 101A, 101B and 101C functions as a master of the control system 1 as a whole.

As an example, in FIG. 2, the timer 101A of the control device 2A is the master. Timers 101B and 101C of controllers 2A and 2C are time synchronized with this master. Thereby, it is possible to mutually synchronize the time among the plurality of control devices 2A, 2B and 2C (corresponding to time synchronization (1) in the figure).

By time synchronization (1), time synchronization (2) and (3), the timers of the control devices 2A, 2B and 2C are synchronized with each other, and the timers of the field devices 90 connected to each control device 2 are synchronized with each other. will do.

FIG. 3 is a diagram explaining data communication of the distributed system 300 according to the present embodiment. In each figure after FIG. 3, "NW" is an abbreviation for network. Referring to FIG. 3, data is exchanged between control device 2A and a plurality of field devices 90A, 90B and 90C connected to network 110 according to a predetermined cycle based on time-synchronized timers. The predetermined period is based on, for example, the control period.

Also between the control device 2B and the plurality of field devices 90D, 90E and 90F, and between the control device 2C and the plurality of field devices 90G, 90H and 90I, according to a predetermined cycle based on the time-synchronized timers. , data is exchanged. Control operations of the control device 2 and the field device 90 are realized by exchanging data through such “lower network (NW) communication” on the network 110 .

Between the control devices 2A, 2B, and 2C connected to the upper network 11, data collected from the field device 90 by each control device 2 through input processing, arithmetic processing, according to a predetermined cycle based on a time-synchronized timer. Output data generated by is exchanged. By exchanging data by such "upper network (NW) communication" on the network 11, the field device 90 connected to the control device 2A, the field device 90 connected to the control device 2B, and the control device 2C are connected. The field devices 90 can work together. “Upper network (NW) communication” on network 11 may include communication between networks 12 , 13 , 14 and control device 2 .

By "lower network (NW) communication" and "upper network (NW) communication", the control timing of the field device 90 can be synchronized between the different processes that constitute the distributed system 300, and the required takt time can be achieved. can meet the time.

<C. Configuration and Time Synchronization Processing>
The configuration of the devices that make up the distributed system 300 will be described. FIG. 4 is a block diagram showing a hardware configuration example of the control device 2 according to this embodiment. FIG. 5 is a block diagram showing a hardware configuration example of the support device 500 according to this embodiment.

(c1. Configuration of control device 2)
Referring to FIG. 4, control device 2 includes processor 102, chipset 104, main memory device 106, secondary memory device 108, upper network controller 105, USB (Universal Serial Bus) controller 107, A memory card interface 109 , a field network controller 118 , a counter 126 and an RTC (Real Time Clock) 128 are included.

The processor 102 is composed of a CPU (Central Processing Unit), MPU (Microprocessor unit), GPU (Graphics Processing Unit), etc., reads various programs stored in the secondary storage device 108, and expands them to the main storage device 106. By executing the command, control according to the controlled object and various processes described later are realized. The secondary storage device 108 is configured by, for example, a non-volatile storage device such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive). The main memory device 106 is composed of a volatile memory device such as DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory).

The chipset 104 realizes the processing of the control device 2 as a whole by controlling the processor 102 and each device.

Communication cycle data 200 is stored in the main storage device 106 . The secondary storage device 108 stores not only system programs for realizing basic functions, but also user programs created according to the manufacturing devices and facilities to be controlled. Furthermore, the secondary storage device 108 also stores a time-series database as described later.

The host network controller 105 exchanges data with the manufacturing execution system 400 or devices on the cloud (see FIG. 1) via the host network 11 . The USB controller 107 controls data exchange with the support device 500 via a USB connection.

The memory card interface 109 is configured such that a memory card 116 can be attached/detached, and data can be written to the memory card 116 and various data (user program, trace data, etc.) can be read from the memory card 116. ing.

The counter 126 is used as a time reference for managing execution timings of various processes in the control device 2 . Counter 126 can be a "supervisory timer" or a "reference timer." In the time synchronization (1) of FIG. 2, the counter 126 of the control device 2A can constitute a reference timer, and the counters 126 of the control devices 2B and 2C can constitute a management timer. Counter 126 typically increments or decrements the counter value at predetermined intervals. The counter 126 may be implemented using a hardware timer such as a high precision event timer (HPET: High Precision Event Timer) placed on the system bus that drives the processor 102, or an ASIC (Application It may be implemented using a dedicated circuit such as Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array).

The RTC 128 is a kind of counter with a clock function, and provides the current time to the processor 102 and the like.

The field network controller 118 controls data exchange with other devices including the field device 90 via the network 110 . The field network controller 118 has a counter 119 used as a time reference for managing timing with other devices. In FIG. 4, the timer 91 of the field device 90 is indicated by counters 91A, 91B, .

For the counters ( counters 91A and 91B) of devices such as the counter 119 and the field device 90, the same configuration as the counter 126 described above can be adopted. Counter 119 is synchronized with counter 126 .

The field network controller 118 functions as a communication master for performing periodic communication via the network 110, and calculates the difference between the counter value indicated by the counter of each device connected to the fieldbus and the counter value indicated by the counter 119. is successively monitored, and if necessary, a synchronization signal is output for instructing correction to a device in which a discrepancy has occurred in the counter value. In this way, the field network controller 118 has a synchronization management function of giving a command to the device to match the counter value indicated by the counter of the device with the counter value indicated by the counter 119 .

FIG. 4 shows a configuration example in which necessary functions are provided by the processor 102 executing a program. (Application specific Integrated Circuit) or FPGA (Field-Programmable Gate Array), etc.). Alternatively, the main part of the control device 2 may be realized using hardware conforming to a general-purpose architecture (for example, an industrial personal computer based on a general-purpose personal computer). In this case, virtualization technology may be used to run multiple OSs (Operating Systems) for different purposes in parallel, and to run necessary applications on each OS.

In the control system 1 according to the present embodiment, the control device 2 and the support device 500 are configured as separate units, but a configuration is adopted in which all or part of these functions are integrated into a single device. You may

(c2. Configuration of support device 500)
Referring to FIG. 5, support device 500 corresponds to an information processing device such as a computer. The support device 500 includes portable and stationary information processing devices. The support device 500 includes a CPU (Central Processing Unit) 501, a memory 502 composed of a volatile storage device such as a DRAM (Dynamic Random Access Memory), a timer 503, and a hard disk composed of a non-volatile storage device such as an HDD. 504 , an input interface 505 , a display controller 506 , a communication interface 507 and a data reader/writer 508 . These units are connected via a bus 509 so as to be able to communicate with each other.

The input interface 505 mediates data transmission between the CPU 501 and input devices such as a keyboard 510, a mouse (not shown), and a touch panel (not shown). The display controller 506 is connected to the display 511 and displays the results of processing in the CPU 501 and the like. Communication interface 507 communicates with control device 2 or device/line management device 190 via USB. Data reader/writer 508 mediates data transmission between CPU 501 and memory card 512, which is an external storage medium.

Note that the memory card 116 in FIG. 4 and the memory card 512 in FIG. 5 include a volatile storage medium or a non-volatile storage medium, for example, CF (Compact Flash: registered trademark), SD (Secure Digital), and other general-purpose storage media. It includes a semiconductor storage device, a magnetic storage medium such as a flexible disk, or an optical storage medium such as a CD-ROM (Compact Disk Read Only Memory).

The hard disk 504 stores various programs and data. FIG. 5 particularly shows programs and data related to the setting support tool 560 among the tools of the support device 500 . The hard disk 504 stores a setting support program 561 and specification data 550 indicating specifications of the control system 1 or distributed system 300 .

More specifically, the setting support program 561 includes an item setting program 565 for setting items for calculating the communication cycle, a range calculation program 570 for calculating the range of the communication cycle, and the calculated cycle range displayed on the display. 511 to present to the user, a determination program 590 for determining the communication cycle based on user operation, and communication cycle data 200 indicating the determined communication cycle to each control device 2. and a setting program 595 of . The range calculation program 570 includes a first calculation program 571 for calculating the above-described first communication cycle based on the processing load of each control device 2 and a second calculation program for calculating the above-described second communication cycle based on the network load. program 572; The determination program 590 includes a user assistance program 591 that assists the user in resetting the communication cycle range, and an evaluation program 592 that evaluates the communication cycle determined based on the user's operation.

(c3. Software configuration example of control device 2)
Next, a software configuration example of the control device 2 configuring the control system 1 according to the present embodiment will be described.

FIG. 6 is a block diagram showing a software configuration example of the control device 2 according to this embodiment. Referring to FIG. 6 , control device 2 includes execution engine 150 , time series database 180 , host connection program 192 and gateway program 194 .

The execution engine 150 constitutes one type of program that executes various programs under the execution environment of various programs. Typically, this execution environment is provided by processor 102 of control device 2 reading a system program stored in secondary storage device 108, developing it in main storage device 106, and executing it.

More specifically, the execution engine 150 includes a control program 152, a variable management program 160, an input program 172, and an output program 174 for realizing control-related processing related to control of the field device 90. The execution engine 150 further includes a time synchronization program 177 for realizing time synchronization processing, and a gateway program 194 and a higher connection program 192 for realizing various processing including service processing related to control. Execution engine 150 also includes a scheduler program 170 that manages the execution order of programs.

The control program 152 typically consists of a user program 154, a database writing program 156, and a serialization communication program 158. The user program 154 corresponds to the main part that provides the control calculation function, and can be arbitrarily configured according to the manufacturing equipment or equipment to be controlled by the control device 2 . The user program 154 can be defined, for example, by ladder logic using function blocks.

The database writing program 156 is called by instructions defined in the user program 154 and writes specified data to the time series database 180 . The serialization communication program 158 serializes data written from the database writing program 156 to the time-series database 180 . The gateway program 194 communicates with devices on the cloud. For example, the time-series data 182 of the time-series database 180 is provided to a device that provides IoT services on the cloud. Database writing program 156, serialization communication program 158, and gateway program 194 may be optional components.

The variable management program 160 manages values that can be used by the execution engine 150 in the form of variables. More specifically, the variable management program 160 stores system variables indicating the state of the control device 2, device variables indicating values held by various devices such as the field device 90 connected to the control device 2, and control device variables. 2 manages user variables that indicate values held by the user program 154 executed in step 2.

The input program 172 provides a function of acquiring input data from field devices 90 including devices such as actuators and sensors connected to the control device 2 . The output program 174 outputs command values (output data) calculated by the user program 154 executed in the control device 2 to the field device 90 which is a target device connected via the network 110 . In this embodiment, the time synchronization program 177 mainly implements the processing of time synchronization (1) shown in FIG. Time synchronization processing will be described later with reference to FIG.

The scheduler program 170 manages the allocation of resources, including the processor 102, execution timing, etc., for the processes or tasks of the control device 2 according to the execution priorities assigned to the processes or tasks. Such processes or tasks include processes or tasks that can be generated by the control device 2 executing the control program 152, the variable management program 160, the input program 172, the output program 174, the time synchronization program 177, and the like. be

The time-series database 180 is typically located in the main storage device 106 or the secondary storage device 108, and has the function of storing data and responding to external requests (queries) with specified data. Equipped with a search function to Time series database 180 stores time series data 182 written by database writing program 156 . That is, the time-series database 180 stores at least part of the input data, the output data, the calculation data calculated in the control calculation by the control program 152, the manufacturing data, and the event data in time series.

The host connection program 192 exchanges data with external devices connected to the host network 13 such as the manufacturing execution system 400 . In the control device 2 according to the present embodiment, input data and calculation data can be output from the control device 2 to the manufacturing execution system 400 and manufacturing information can be received from the manufacturing execution system 400 .

In this embodiment, the manufacturing execution system 400 has the time series DB 450 of FIG. In this case, instead of the host connection program 192, or as part of the host connection program 192, a database connection program 193 (the database is indicated as "DB" in the figure) can be provided. By executing the database connection program 193 , the time series data 182 of the time series database 180 in the control device 2 can be transferred to the manufacturing execution system 400 and stored in the time series DB 450 .

The variable management program 160 manages the input data (state values) that the input program 172 acquires from the field and the manufacturing data that the upper connection program 192 acquires from the manufacturing execution system 400 as variables. The user program 154 refers to system variables, device variables, and user variables managed by the variable management program 160, executes a control operation specified in advance, and outputs the execution result (output data) to the variable management program 160. do.

(c4. Module configuration of support device 500)
FIG. 7 is a diagram schematically showing the module configuration of support device 500 according to the present embodiment. The modules shown in FIG. 7 are implemented by executing programs corresponding to the modules stored in the hard disk 504 of FIG.

More specifically, the setting support tool 560 includes an item setting unit 520 corresponding to the item setting program 565 and a range calculating unit 530 corresponding to the range calculating program 570. The range calculator 530 has a first calculator 531 and a second calculator 532 corresponding to the first calculator 571 and the second calculator 572 . The setting support tool 560 further includes a range display section 535 corresponding to the range display program 580 , a determination section 536 corresponding to the determination program 590 , and a setting section 539 corresponding to the setting program 595 . The determination unit 536 includes a user support unit 537 corresponding to the user support program 591 and an evaluation unit 538 corresponding to the evaluation program 592 . The user support unit 537 includes a user interface UI (User Interface) 53 . The support device 500 is associated with the setting support tool 560 and includes a display control unit 540 that controls the display 511 according to display control data based on the output from the setting support tool 560, and a user operation on the support device 500 via the keyboard 510. It has an operation receiving unit 541 for receiving.

The setting support tool 560 provides a UI including a display control unit 540 and an operation reception unit 541. In this embodiment, UI is a concept including a graphical user interface (GUI). The UI presents information from the setting support tool 560 to the user via the display 511 and accepts user operations on the setting support tool 560 via the keyboard 510, realizing a so-called interactive environment.

The item setting unit 520 sets data retrieved from the specification data 550 as items for calculating the range of the communication cycle. Specification data 550 represents design specifications for control system 1 or distributed system 300 . More specifically, the specification data 550 includes, for each control device 2, UPG specification data 551 indicating the specification of UPG (User Program) executed in the control device 2, and control data indicating the control cycle in each control device 2. Cycle data 552, system configuration data 553 indicating the configuration of the system, upper NW (abbreviation of network) load data 554 indicating the load related to the network 11 by communication via the upper networks 12, 13, 14, and data necessary for the system. synchronization accuracy 555.

The UPG specification data 551 indicates specifications of a UPG program for realizing control-related processing related to control executed in the control device 2 . More specifically, the UPG programs include control program 152 , variable management program 160 , input program 172 and output program 174 . The UPG specification data 551 includes, for example, the size of each program (number of instructions, number of steps, etc.).

The system configuration data 553 includes the number of devices (control devices 2) connected to the network 11 (also referred to as the number of nodes), the topology, the type of each device, and various performance information. The performance information includes the processing performance of each control device 2 (processor operation speed, memory size/speed, etc.), the transmission performance of the network 11 (communication speed, various bands, etc.), and the time synchronization performance of each control device 2 . The information indicating the performance of time synchronization is a value having a correlation with the synchronization accuracy, for example, the resolution of the time stamp described later, the sync retention time, the maximum frequency drift, the maximum frequency jitter, etc., and one synchronization It may include the bandwidth required for message communication and the bandwidth required during execution of control-related processing.

The programs stored in the hard disk 504 of FIG. 5 may be provided as individual programs as shown in FIG. 5, or two or more programs may be combined and provided as one program.

(c5. Scheduler and Priority)
The scheduler program 170, when executed, implements a scheduler that manages the execution order of processes in a control cycle. The scheduler allocates resources, including the processor 102, to the processes or tasks of control-related processing, time synchronization processing, and service processing according to execution priorities pre-assigned to the processing.

In this embodiment, the highest priority is assigned to the process or task of control-related processing, and the lowest priority is assigned to the process or task of time synchronization processing and service processing. The scheduler allocates the processor 102 to the control-related process with the highest priority in the control cycle, and allocates the processor 102 to the low-priority process in the remaining "slack time" after the execution of the control-related process is completed. As a result, each control device 2 is guaranteed to execute the control-related processing within the control period, and the data exchanged between the control devices 2 is preferentially transmitted to the network 11. We can guarantee the time. In this embodiment, in order to simplify the explanation, the time synchronization process is mainly executed during the "slack time" of the control cycle.

(c6. Time Synchronization Processing)
For time synchronization, the control system 1 can adopt a high precision time synchronization protocol such as IEEE1588, IEEE802.1AS, IEEE802.1AS-Rev. For example, IEEE 1588 defines PTP (Precision Time Protocol) as a high-precision time synchronization protocol. PTP can be applied to a communication system that includes a master, which is a reference timer, and a slave, which is a timer that synchronizes to the reference timer. In PTP, frames with synchronization messages are periodically exchanged between the master and the slave, and based on the information obtained in the process, the time of the slave is adjusted to match the time of the master.

FIG. 16 is a diagram showing an example of the PTP time synchronization processing sequence. In the sequence shown in FIG. 16, time synchronization between the master and the slave is achieved by linking the master M and the slave S. FIG. For simplicity of explanation, master M communicates with slave S without a repeater.

First, the master M sends a Sync message 169 to the slave S at time T1, and the slave S receives the Sync message 169 from the master at time T2. Master M then sends a Follow_Up message to slave S including information indicating time T1. When slave S receives the Follow_Up message, it records time T1 and time T2.

Next, slave S sends a Delay_Req message to master M at time T3. When the master M receives the Delay_Req message at time T4, it sends a Delay_Resp message to the slave S. The Delay_Resp message contains information indicating time T4. When the slave S receives the Delay_Resp message, it can confirm that the master M has received the Delay_Req message, so it records time T3 and time T4.

The slave S records times T1, T2, T3, and T4 (that is, four time stamps). The slave S synchronizes the time of the slave S with the master M so as to eliminate errors including communication delay time based on these time stamps. In this embodiment, the magnitude of the error represents "synchronization accuracy". Master M and slave S correspond to timer 101A of control device 2A and timer 101B of control device 2B (or timer 101C of control device 2C), respectively.

In the time synchronization process, the control device 2 executes a correction process for correcting the time of the slave S so as to eliminate the above error. Correction processing is realized by executing the correction program 178 . In this embodiment, the upper limit of the amount of correction per time is determined. Therefore, when the error is large, it is necessary to repeat the correction process multiple times, that is, to complete the correction process, it is necessary to take one or more control cycles. If the master sends the Sync message 169 (or the slave S receives the Sync message 169) before completing the correction process, the correction process based on the new time stamp cannot be executed immediately. decreases. The setting support tool 560 is configured to set a communication cycle that guarantees completion of correction processing.

In the present embodiment, "time synchronization processing" includes message communication processing related to the communication sequence of FIG. “Communication cycle” indicates a cycle for transmitting a synchronization message between master M and slave S via network 11 . More specifically, the communication cycle indicates the cycle in which the master M transmits the Sync message 169 to the slave S or the cycle in which the slave S receives the Sync message 169 from the master M. The scheduler of each control device 2 allocates the processor 102 to message communication processing according to the communication cycle indicated by the communication cycle data 200 set by the setting support tool 560 . Thereby, each control device 2 can set the timing of communicating the Sync message 169 when the control device 2 completes the correction process, and as a result, accurate correction can be guaranteed.

The time synchronization protocol according to the present embodiment is not limited to PTP, and other wired or wireless communication protocols can be applied. For example, NTP (Network Time Protocol) or SNTP (Simple Network Time Protocol), GPS (Global Positioning System) or Synchronous Ethernet (registered trademark) protocol, CS-NMS (Clock-sampling mutual network when NW bandwidth is limited) Synchronization), RBS ((Reference Broadcast Synchronization) and RBIS (Reference Broadcast Infrastructure Synchronization) protocols can also be applied. GPS and synchronous Ethernet protocols are not NW load related.

<D. Flowchart>
FIG. 8 is a flow chart showing a schematic process of communication cycle setting according to the present embodiment. The process of FIG. 8 includes a process of setting a "period range" which is a range in which the communication period of the synchronization message can be set, a process of determining the communication period from the period range based on the user's operation, and distributing the determined communication period. and processing to be set in the type system 300 .

The user operates the keyboard 510 to create specifications for the distributed system 300, and the CPU 501 stores specification data 550 indicating the created specifications in the hard disk 504 (step S1). The CPU 501 executes the process of step S3 as the item setting unit 520 (step S3). More specifically, CPU 501 displays specification data 550 on display 511 . By operating the keyboard 510 , the user activates the setting support tool 560 and inputs item data for setting the period range to the support device 500 .

The CPU 501, as the setting support tool 560, executes the processes of steps S5 to S11. More specifically, the CPU 501, as the item setting unit 520, sets item data based on the user operation, and the CPU 501, as the range calculation unit 530, calculates the periodic range based on the item data (step S5). , the range display unit 535 presents the calculated periodic range to the user via the display 511 (step S7). More specifically, in step S<b>7 , the CPU 501 causes the display 511 to display an image indicating the periodic range via the display control unit 540 . The CPU 501 , as the determination unit 536 , determines a user-specified communication cycle from within the cycle range displayed on the display 511 based on the user's operation from the keyboard 510 .

The CPU 501 determines whether or not a user operation for determining the communication cycle has been received via the operation receiving unit 541 (step S9). As 539, notification of the communication cycle data 200 indicating the determined communication cycle is transmitted to each control device 2 connected to the network 11 (step S11). Each control device 2 of the distributed system 300 sets the communication cycle data 200 notified from the support device 500 to the control device 2 (step S17).

On the other hand, if the CPU 501 determines that the user operation for determining the communication cycle has not been received (NO in step S9), for example, if it has determined that the activation operation of the user support function for resetting the cycle range has been received, the CPU 501 The user support unit 537 displays support information for resetting on the display 511 (step S13). Based on the displayed reset support information, the user operates the keyboard 510 to input information for resetting the period range to the support device 500 (steps S15 and S1). The CPU 501 recreates (changes) the specification data 550 based on the information input by the user (step S3). As a result, the setting support tool 560 proceeds to step S5, activates the range calculation unit 530 based on the item data of the changed specification data 550, causes the range calculation unit 530 to recalculate the period range, and instructs the user to Presented (steps S5, S7).

According to the process of FIG. 8, the user can set the period range while interacting with the setting support tool 560 and determine the communication period from within the set period range.

<E. Cycle range setting processing>
In this embodiment, the CPU 201, as the setting support tool 560, sets the period range using the lower limit and upper limit. More specifically, the setting support tool 560 sets a period range having a width from a communication period based on the processing load of control-related processing of each control device 2 and a network load to a communication period based on the required synchronization accuracy 555. set.

FIG. 9 is a diagram showing an example of calculation processing of the first communication cycle based on the processing load according to this embodiment. FIG. 10 is a diagram showing an example of calculation processing of the second communication cycle based on network load according to the present embodiment. FIG. 11 is a diagram showing the flow of data in setting the periodic range in this embodiment. As the setting support tool 560, the CPU 501 sets the periodic range by processing data according to the flow shown in FIG. In FIG. 11, data flow is shown in association with steps S1-S7 of the process of FIG.

A procedure for calculating the period T _min of the lower limit value and the period T _max of the upper limit value of the period range will be described with reference to FIGS. 9 , 10 and 11 . The CPU 501 executes the process of FIG. 9 as the first calculator 531 . More specifically, the CPU ₅₀₁ acquires a unit time Call for calculating the processing load. The unit time _Call is a fixed time, and indicates, for example, the control cycle indicated by the control cycle data 552 or one second. Further, the CPU 501 calculates the processing time (processing load) required for control-related processing from the program size indicated by the UPG specification data 551 and the operation speed of the processor 102 indicated by the system configuration data 553, and converts the calculated value into unit time. The processing time per unit time C _all is set to C _app , and the CPU 510 calculates the extra processing time C _syn per unit time C _all according to the formula C _syn =(C _all −C _app ). In addition, the CPU 501 determines the processing time C1 indicating the processing time (processing load) required for _one time synchronization process in the control device 2, and the size of the time synchronization program 177 indicated by the UPG specification data 551 and the system configuration data 553 indicate the processing time C1. It is calculated from the calculation speed of the processor 102 . The CPU 501 calculates the first communication cycle TC _min =(C ₁ /C _syn ) for the control device 2 . The CPU 501 calculates the first communication cycle TC _min for each control device 2 according to the procedure described above. The longest first communication cycle TC _min among the first communication cycles TC _min of each control device 2 is a candidate for the cycle T _min described later.

The CPU 501 executes the process of FIG. 10 as the second calculator 532 . More specifically, the CPU 501 determines the bandwidth N _all indicating the maximum amount of data that can be transmitted per unit time with respect to the network 11, and the data transmitted through the network 11 in communication processing related to UPG (control-related processing, etc.). Band N _app is used to calculate the band N _syn according to the equation N _syn =(N _all -N _app ). Bandwidth N _all can be obtained from the transmission performance of network 11 in system configuration data 553 . Although the band N _all is not limited, for example, a maximum band of 100 mega bps (bits per second) or 1 giga bps of an EtherNet (registered trademark) communication cable can be applied. The data amount N _app corresponds to the communication load (NW load) related to the network 11 in executing UPG. The CPU 501 acquires the usage bandwidth of the UPG that involves network communication among the UPGs of the control-related processing from the UPG specification data 551, and calculates the NW load from the sum of the usage bandwidth of the acquired UPG and the bandwidth indicated by the upper NW load data 554. Calculate the corresponding band N _app . The band N _syn indicates a band (transmission data amount, NW load) available for time-synchronous message communication. When the network 11 is a completely unused vacant band, the CPU 501 configures the band N ₁ (transmission data amount, NW load) used in one time synchronization message communication (communication sequence in FIG. 16). It is obtained from the time synchronization performance of each control device 2 in the data 553 or measured in the network 11 . The CPU 501 calculates the communication required time for time synchronization in the network 11 during operation, that is, the second communication cycle Tn _min =(N ₁ /N _syn ).

The CPU 501, as the range calculation unit 530, compares the longest cycle of the first communication cycles TC _min of each control device 2 with the second communication cycle Tn _min , and determines the longer one as the cycle T _min . set to The period T _min can be the lower limit of the period range.

The CPU 501 also calculates the communication cycle T _max from the necessary synchronization accuracy 555 and the transmission performance of the network 11 acquired from the system configuration data 553 and the value indicating the time synchronization performance of each control device 2 . The communication cycle T _max can be the upper limit of the cycle range.

An arithmetic expression for calculating the upper limit value _Tmax and an arithmetic expression for calculating the PTP synchronization accuracy E will be described. An arithmetic expression for calculating the synchronization accuracy E is known to be expressed by, for example, the following arithmetic expression (1).

E=(0.5×b×(sync) ² )+(a×b×c×d)+e (Formula 1)
In the above equation (1), the variable sync used in parentheses in the first term indicates the transmission cycle of the sync message 169, that is, the communication cycle for time synchronization. Note that the transmission cycle of other messages may be set to the variable sync. Other variables in equation (1) indicate a value that depends on the time synchronization performance of the node (control device 2) connected to the network 11 and the maximum number of nodes connected to the network 11. As the number of nodes increases, Synchronization accuracy E calculated by (Equation 1) decreases.

In step S5, the CPU 501 acquires the values of the variables a, b, c, d, and e from the time synchronization performance of the node (control device 2) of the system configuration data 553, and these acquired values and the necessary The variable sync is calculated from (Equation 1) using the synchronization accuracy 555 (that is, corresponding to "E" in Equation 1). As a result, the value of the variable sync that satisfies the required synchronization precision 555, that is, the communication period _Tmax of the synchronization message is calculated. The CPU 501 sets the communication cycle _Tmax indicated by the calculated variable sync as the upper limit value of the cycle range.

According to the above (Formula 1), if the value of the variable sync indicating the communication cycle is fixed, the synchronization accuracy E decreases as the number of control devices 2 connected to the network 11 increases. This point is supplemented with a graph. FIG. 12 is a graph schematically showing the relationship between synchronization accuracy and the number of nodes. In FIG. 12, the vertical axis indicates the synchronization accuracy (magnitude of error), and the horizontal axis indicates the number of nodes (the number of control devices 2). FIG. 12 graphically shows changes in synchronization accuracy when the values 121 and 123 of the variable Sync are changed based on the simulation results. As shown in the graph, if the communication cycle is the same, the synchronization accuracy E decreases as the number of control devices 2 connected to the network 11 increases. Therefore, when securing the necessary synchronization accuracy 555, the value of the variable sync decreases as the number of control devices 2 increases. If synchronous communication is executed at a communication cycle with a value greater than the value of this variable sync, the required synchronization accuracy 555 cannot be satisfied. Based on these backgrounds, the CPU 501 can acquire the upper limit value (communication cycle T _max ) of the cycle range capable of satisfying the required synchronization accuracy 555 from the system configuration data 553 (the number of nodes, etc.) and (Formula 1).

<F. Evaluation of UI in Cycle Range and Synchronization Accuracy>
FIG. 13 is a diagram showing an example of a UI screen for communication cycle setting according to this embodiment. The CPU 501, as the range display unit 535, executes the process of step S7. The UI screen of FIG. 13 is an example of a screen for accepting a user operation specifying a communication cycle, and is displayed in step S7 of FIG.

The screen of FIG. 13 shows a cycle range (T _min to T _max ), and an indicator 601 indicating the default cycle T _def recommended by TSN and the median value T _cen of T _min to T _max in association with the cycle range, It includes a communication cycle table 609 having reference values 602 for each of the communication cycles T _min , T _def , T _cen , T _max and the user-configured cycle T _usr .

The reference value 602 of the communication cycle table 609 is a value (unit: ms) indicating the communication cycle 31 for each of the corresponding communication cycles T _min , T _def , T _cen , T _max and the cycle T _usr , and based on the communication cycle. synchronization accuracy 32 (unit: μs) that can be ensured for a period of time 31, a processing load 33 related to the processor 102 and a NW load 34 related to the network 11 when synchronous communication processing is executed in the communication cycle 31. FIG. A processing load 33 (unit: %) indicates processing time C _sync /unit time, and a NW load 34 (unit: %) indicates data amount N _sync /bandwidth N _all . CPU 501 calculates reference value 602 (synchronization accuracy 32, processing load 33 and NW load 34) is calculated. In FIG. 13, among the reference values 602, the required synchronization accuracy 555 indicated by the specification data 550, for example 10 μs, is marked with an emphasis mark (star mark in FIG. 13). Reference values 602 in FIG. 13 are exemplary and not limiting.

At step S15 in FIG. 8, the user can use the reference value 602 as support information for setting the communication cycle. For example, the user designates the default period T _def (125 ms) recommended by TSN, for example, from the reference value 602 as a period having accuracy higher than the required synchronization accuracy 555 . The CPU 501 determines the default period T _def as the set period 604 based on the specifying operation.

(f1. Evaluation of communication cycle determined by user)
The user can also determine a period other than the communication period 31 indicated by the reference value 602 in FIG. In that case, the CPU 501, as the evaluation unit 538, evaluates the synchronization accuracy based on the communication cycle set by the user. More specifically, when each control device 2 executes the time synchronization process in accordance with the synchronization message transmitted based on the determined set cycle 604, the CPU 501 calculates the synchronization accuracy E so that the set cycle 604 Evaluate the synchronization accuracy corresponding to

The user operates the keyboard 510 to set the communication cycle 31 (setting cycle 604) in the item 603. The CPU 501 , as the evaluation unit 538 , calculates the synchronization accuracy acquired based on the communication cycle 31 set in the item 603 and sets the calculated value as the synchronization accuracy 32 in the item 603 . When calculating the synchronization accuracy 32 of the item 603, the CPU 501 substitutes the value of the communication cycle 31 set by the user for the variable sync, and calculates the synchronization accuracy E of the communication cycle 31 by a predetermined arithmetic expression such as (Eq. is calculated, the processing load 33 and the NW load 34 are calculated, and the calculated values are set in the item 603 . On the UI screen of FIG. 13, the user determines the information evaluated for the communication cycle 31 (set cycle 604), that is, the synchronization accuracy 32, the processing load 33, and the NW load 34, and finally determines the communication cycle 31 as the set cycle 604. It can be used as support information for determining whether or not to

In the present embodiment, the evaluation by the evaluation unit 538 is the calculation of the synchronization accuracy 32, the processing load 33 and the NW load 34, but is not limited to the calculation of all of these, and the synchronization accuracy 32, the processing load 33 and the NW load 34, in particular the calculation of the synchronization accuracy 32 .

In step S11 of FIG. 8, the CPU 501 sends notification of the communication cycle data 200 indicating the set cycle 604 determined by the user's operation on the UI screen of FIG.

(f2. Presentation of period range and another example of user operation)
FIG. 14 is a diagram showing another example of the UI screen for communication cycle setting according to the present embodiment. FIG. 15 is a diagram showing an example of a UI screen for adjusting the setting condition of the periodic range according to this embodiment. FIG. 13 _shows a case where the condition (T _{max ≧} T _min ) is satisfied. The communication cycle cannot be determined in the cycle range where the condition of (T _max <T _min ) is satisfied.

The user operates the button 605 in FIG. 14 to activate the setting support function of the user support unit 537 in order to acquire the period range that enables determination of the communication period. When the button 605 is operated, the CPU 501 causes the display 511 to display the setting support information 606 of FIG. 15 as the user support unit 537 . The unit ms/s shown in FIG. 15 is a unit of processing load and represents processing time (ms) per unit time (s).

The UI screen of FIG. 15 is provided by UI53. The UI screen includes setting support information 606 , a communication cycle table 609 and buttons 608 . The setting support information 606 includes items of the specification data 550 that can be adjusted to satisfy the condition (T _min ≤ T _max ). The setting support information 606 includes a policy 611 (reducing T _min 61a and increasing T _max 61b) representing a change mode of the period range for satisfying the condition of (T _min ≤ T _max ), a method 612, a current state 613 indicating the current value of an item to be adjusted (changed, etc.) in order to implement the method 612, a condition 614 indicating the adjustment amount of the value of the item indicated by the current state 613, and the current state 613 and an input 615 indicating the value after user adjustment operation of the indicated item. A current state 613 indicates the current value of the item to be adjusted in the specification data 550 . A condition 614 indicates an adjustment amount (increase or decrease and value) of the item value indicated by the current state 613 in order to satisfy (T _min ≦T _max ).

The user sets the value after adjustment (change) of one or more items among the items of the current state 613 of the setting support information 606 in FIG. The user can adjust the value of the item based on the condition 614 corresponding to the item.

The items of the current status 613 include the control period for calculating the first period, the processing performance of each control device 2, the size of control-related processing and time synchronization processing, and the like. Items of the current status 613 include the transmission performance of the network 11, the bandwidth required for processing by each control device 2, the time synchronization performance of each control device 2, and the like, for calculating the first cycle. The item of the current status 613 also includes an item of necessary synchronization accuracy. The UI 53 accepts a user operation for adjusting at least one item from the screen of FIG. 15 .

In FIG. 15, in adjusting the value of the item, for example, the user sets the adjusted NW band value 607 in the input 615 by the adjusting operation. When the user operates the button 608 , the CPU 501 activates the range calculation unit 530 . As the range calculation unit 530, the CPU 501 recalculates the range of the communication cycle based on the values of the items after the adjustment operation received in the input 615 of FIG. The CPU 501 sets the recalculated period range data in the communication period table 609 of FIG. Based on the values set in the communication cycle table 609, the user can determine whether to determine the communication cycle within the recalculated cycle range, and whether to reflect the values of each item of the input 615 to the system specification data 550. can be judged.

The case where the periodic range is recalculated using the UI screen of FIG. 15 may be other than the case where the condition (T _max <T _min ) is satisfied. For example, even if the condition of (T _max ≧T _min ) is satisfied, the user wishes to change the period range (that is, recalculate the period range to change the value of T _max or T _min ) 15, the user can cause the CPU 501 to recalculate the period range based on the value of the input 615 after adjustment in FIG. .

According to the setting support tool 560 according to the present embodiment, based on the processing load of each control device 2 and the NW load of the network 11, a periodic range that can satisfy the required synchronization accuracy 555 is calculated and presented to the user. be. The user can use the setting support tool 560 when designing the distributed system 300 (when creating the specifications) or when creating the specification data 550 when designing the system. It is possible to reduce the man-hours for such debugging work, that is, the man-hours for trial-and-error setting of items related to the communication cycle.

<G. Program>
The CPU 501 of the support device 500 executes a setting support program 561 to provide the user with a setting support tool 560 for period setting. Hard disk 504 can store programs and data for realizing setting support tool 560 .

Programs and data for realizing the setting support tool 560 may be downloaded to the hard disk 504 via the communication interface 507 and various communication lines. Alternatively, it may be downloaded to hard disk 504 via memory card 512 . The memory card 512 stores information such as programs by electrical, magnetic, optical, mechanical or chemical action so that computers, other devices, machines, etc. can read the information such as programs. It is a medium to Support device 500 may acquire programs or data relating to setting support tool 560 from this memory card 512 .

A program can be executed by one or more processors such as the CPU 501, or by a combination of processors and circuits such as ASIC (Application Specific Integrated Circuit) and FPGA (Field-Programmable Gate Array).

<H. Note>
The present embodiment as described above includes the following technical ideas.
[Configuration 1]
An information processing device (500) for processing communication cycles of a plurality of control devices (2A, 2B, 2C) connected to a FA (factory automation) network (11),
each of the plurality of controllers,
Execute processing including control-related processing related to control and time synchronization processing for synchronizing time between control devices according to the synchronization message (169),
The information processing device is
A range calculation unit (530) for calculating a range of cycles for communicating the synchronization message to each of the control devices via the network,
The range calculation unit
For each control device, a margin time excluding the execution time of the processing based on the processing load of the control-related processing in a predetermined cycle, and the time required for one time synchronization processing executed by the control device a first calculation unit (531) for calculating the first communication cycle (TC _min ) from
A second calculation unit that calculates a second communication cycle (Tn _min ) from the surplus bandwidth obtained by removing the bandwidth based on the network load from the available bandwidth of the network and the bandwidth required for communication of one synchronization message. (532), including
Based on the longer communication cycle (T _min ) of both the longest cycle of the first communication cycle and the second communication cycle of each of the control devices, and a predetermined synchronization accuracy (555) An information processing apparatus that calculates the range using a communication cycle (T _max ).
[Configuration 2]
The range calculation unit
The information processing apparatus according to configuration 1, wherein the communication cycle and the longer cycle based on the predetermined synchronization accuracy are calculated as the upper limit value and the lower limit value of the range, respectively.
[Configuration 3]
a range display unit (535) for displaying the period range calculated by the range calculation unit on a display (511);
a determination unit (536) for determining a cycle for communicating the synchronization message to each of the control devices via the network, based on a user operation on the information processing device, from among the range of the calculated cycles; The information processing apparatus according to configuration 1 or 2, comprising:
[Configuration 4]
The information processing apparatus according to configuration 3, wherein the range display unit causes the display to display a default cycle (T _def ) according to a communication protocol applied to the network in association with the range.
[Configuration 5]
The information processing device according to configuration 3 or 4, wherein data indicating the period determined by the determining unit is set in each of the control devices.
[Configuration 6]
Any of configurations 3 to 5, further comprising an evaluation unit (538) that evaluates synchronization accuracy when each control device executes the time synchronization process according to the synchronization message transmitted based on the determined cycle 1. The information processing device according to claim 1.
[Configuration 7]
The first calculation unit calculates the margin time and the required time from the first information,
The first information includes items of the predetermined period, the processing performance of each control device, and the sizes of the control-related processing and the time synchronization processing,
The second calculation unit calculates the available bandwidth, the bandwidth based on the network load, and the bandwidth required for communication of one synchronization message from the second information,
The second information includes items of transmission performance of the network, bandwidth required for processing by each control device, and time synchronization performance of each control device,
a UI (user interface) (53) that displays the first information item, the second information item, and the predetermined synchronization accuracy item, and receives a user operation for adjusting at least one item; 7. The information processing apparatus according to any one of configurations 1 to 6.
[Configuration 8]
The UI further includes:
Configuration 7, wherein one or more change modes (61a, 61b) for changing the calculated range, and an item (612) to be adjusted and an adjustment amount (614) associated with each change mode are displayed. Information processing equipment.
[Configuration 9]
The UI further includes:
activating the range calculation unit so as to calculate the range of the communication cycle based on the first information, the second information, and the predetermined synchronization accuracy when the adjustment operation is received from the user; , Configuration 7 or 8, the information processing apparatus.
[Configuration 10]
10. The information processing apparatus according to any one of configurations 1 to 9, wherein each of the plurality of control devices constitutes a distributed control system (300) provided for each different process of the FA.
[Configuration 11]
The control device connects one or more devices to be controlled (90A to 90I),
11. The information processing apparatus according to any one of configurations 1 to 10, wherein the predetermined cycle indicates a control cycle (552).
[Configuration 12]
A method for processing communication cycles of a plurality of control devices (2A, 2B, 2C) connected to a FA (factory automation) network (111),
each of the plurality of controllers,
An execution unit (150) that executes processing including control-related processing related to control and time synchronization processing for synchronizing time between control devices according to a synchronization message (169),
The method includes:
A step (S5) of calculating a period range for communicating the synchronization message to each of the control devices via the network;
The step of calculating the range includes:
For each control device, a margin time excluding the execution time of the processing based on the processing load of the control-related processing in a predetermined cycle, and the time required for one time synchronization processing executed by the control device a step of calculating a first communication cycle (TC _min ) from
calculating a second communication cycle (Tn _min ) from a surplus bandwidth obtained by excluding a bandwidth based on a network load from the available bandwidth of the network and a bandwidth required for communication of one synchronization message;
Based on the longer communication cycle (T _min ) of both the longest cycle of the first communication cycle and the second communication cycle of each of the control devices, and a predetermined synchronization accuracy (555) and calculating the range using a communication period (T _max ).
[Configuration 13]
A program (561) for causing a processor to perform the method of arrangement 12.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

1 Control system, 2, 2A, 2B, 2C Control device, 3A, 3B, 3C Process, 11, 12, 13, 14, 110 Network, 31, 318 Communication cycle, 32, 555, E Synchronization accuracy, 33, Csync processing Load, 34, Nsyn NW load, 53 UI, 90, 90A, 90B, 90C, 90D, 90E, 90F, 90G, 90H, 90I Field device, 126 Counter, 102 Processor, 150 Execution engine, 152 Control program, 154 User program , 156 Database write program, 158 Serialization communication program, 160 Variable management program, 169 Sync message, 170 Scheduler program, 172 Input program, 174 Output program, 177 Time synchronization program, 178 Correction program, 200 Communication cycle data, 300 Distributed system , 500 support device, 510 keyboard, 511 display, 520 item setting unit, 530 range calculation unit, 531 first calculation unit, 532 second calculation unit, 535 range display unit, 536 determination unit, 537 user support unit, 538 evaluation unit , 539 setting unit, 540 display control unit, 541 operation reception unit, 550 specification data, 551 UPG specification data, 552 control cycle data, 553 system configuration data, 554 load data, 560 setting support tool, 561 setting support program, 565 items Setting program, 570 Range calculation program, 571 First calculation program, 572 Second calculation program, 580 Range display program, 590 Decision program, 591 User support program, 592 Evaluation program, 595 Setting program, 601 Indicator, 602 Reference value, 603 Item, 604 setting cycle, 606 setting support information, 609 communication cycle table, 611 policy, 612 method, 613 current situation, 614 adjustment condition, 615 input.

Claims (13)

1. An information processing device that processes communication cycles of a plurality of control devices connected to a FA (factory automation) network,
   each of the plurality of controllers,
   Execute processing including control-related processing related to control and time synchronization processing for synchronizing time between control devices according to a synchronization message,
   The information processing device is
   a range calculation unit that calculates a range of a cycle for communicating the synchronization message to each of the control devices via the network;
   The range calculation unit
   For each control device, a margin time excluding the execution time of the processing based on the processing load of the control-related processing in a predetermined cycle, and the time required for one time synchronization processing executed by the control device a first calculation unit that calculates a first communication cycle from
   a second calculation unit that calculates a second communication cycle from a surplus bandwidth obtained by removing a bandwidth based on a network load from the available bandwidth of the network and a bandwidth required for communication of one synchronization message; ,
   using the longer communication cycle of both the longest cycle of the first communication cycle and the second communication cycle of each of the control devices and a communication cycle based on a predetermined synchronization accuracy; An information processing device that calculates a range.
2. The range calculation unit
   2. The information processing apparatus according to claim 1, wherein the communication cycle and the longer cycle based on the predetermined synchronization accuracy are calculated as the upper limit value and the lower limit value of the range, respectively.
3. a range display unit for displaying the range of the cycle calculated by the range calculation unit on a display;
   a determining unit configured to determine a period for communicating the synchronization message to each of the control devices via the network, based on a user operation on the information processing device, from among the range of the calculated periods. Item 3. The information processing device according to Item 1 or 2.
4. The information processing apparatus according to claim 3, wherein the range display unit causes the display to display a default cycle according to the communication protocol applied to the network in association with the range.
5. The information processing apparatus according to claim 3 or 4, wherein data indicating the cycle determined by the determination unit is set in each of the control devices.
6. 6. Any one of claims 3 to 5, further comprising an evaluation unit that evaluates synchronization accuracy when each control device executes the time synchronization processing according to the synchronization message transmitted based on the determined cycle. The information processing device according to the item.
7. The first calculation unit calculates the margin time and the required time from the first information,
   The first information includes items of the predetermined period, the processing performance of each control device, and the sizes of the control-related processing and the time synchronization processing,
   The second calculation unit calculates the available bandwidth, the bandwidth based on the network load, and the bandwidth required for communication of one synchronization message from the second information,
   The second information includes items of transmission performance of the network, bandwidth required for processing by each control device, and time synchronization performance of each control device,
   A UI (user interface) that displays the first information item, the second information item, and the predetermined synchronization accuracy item, and receives a user operation for adjusting at least one item. 7. The information processing device according to any one of 1 to 6.
8. The UI further includes:
   8. The information processing apparatus according to claim 7, which displays one or more change modes for changing the calculated range, and an item to be adjusted and an adjustment amount in association with each change mode.
9. The UI further includes:
   activating the range calculation unit so as to calculate the range of the communication cycle based on the first information, the second information, and the predetermined synchronization accuracy when the adjustment operation is received from the user; 9. The information processing apparatus according to claim 7 or 8.
10. The information processing apparatus according to any one of claims 1 to 9, wherein each of the plurality of control devices constitutes a distributed control system provided for each different process of the FA.
11. The control device connects one or more devices to be controlled,
    The information processing apparatus according to any one of claims 1 to 10, wherein said predetermined cycle indicates a control cycle.
12. A method for processing communication cycles of a plurality of control devices connected to a FA (factory automation) network,
    each of the plurality of controllers,
    An execution unit that executes processing including control-related processing related to control and time synchronization processing for synchronizing time between control devices according to a synchronization message,
    The method includes:
    calculating a range of cycles for communicating the synchronization message to each of the control devices via the network;
    The step of calculating the range includes:
    For each control device, a margin time excluding the execution time of the processing based on the processing load of the control-related processing in a predetermined cycle, and the time required for one time synchronization processing executed by the control device a step of calculating a first communication cycle from
    calculating a second communication cycle from a surplus bandwidth obtained by excluding a bandwidth based on a network load from the available bandwidth of the network and a bandwidth required for communication of one synchronization message;
    using the longer communication cycle of both the longest cycle of the first communication cycle and the second communication cycle of each of the control devices and a communication cycle based on a predetermined synchronization accuracy; calculating a range.
13. A program for causing a processor to execute the method according to claim 12.

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