JP2010224939A - Control computer and control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce labor in developing a control computer for performing control processing in a plurality of different periods with respect to one or more device to be controlled in a control system and to prevent deterioration in communication performance. <P>SOLUTION: The control computer 120 sets a time limit, such as a transmission period of a program for periodically transmitting a control command value to the device to be controlled, to a communication scheduler 102 with respect to the same. When the communication scheduler 102 receives the control command value output by each program, it brings one or more control command value together in one transmission data and determines transmission timing of the transmission data so as to observe the time limit of each program. The transmission data are transmitted with the determined transmission timing. When a response from the device to be controlled is received after the transmission data are transmitted, a program to process the response is started. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a transmission timing control technique when a control computer that controls one or more control target devices transmits a control command value to the control target device.

  As a control system, there is a control system in which a control computer controls a single or a plurality of control target devices via a network (see Non-Patent Document 1). This control computer controls each device to be controlled by executing a program. The control computer uses an operating system (hereinafter referred to as OS) or dedicated hardware for improving processing performance as necessary. A program related to such control processing generally repeats predetermined processing at a predetermined cycle. Usually, this period is a time constraint imposed on the control processing of the control computer.

EtherCAT (registered trademark), [online], [Search on December 3, 2008], Internet, <URL: http://www.anybus.jp/technologies/ethercat.shtml>

  Here, there is a case where the control computer wants to execute different control processes such as the transmission cycle of the control command value for each control target device. In such a case, in the communication application of the control computer, in order to satisfy the time constraint of the control process described above, a conditional branch that distinguishes the period of each control process must be set. Such setting of conditional branching is very complicated, and there is a problem that it takes time to develop a communication application. Further, there is a problem that it takes time and effort to change, add, or extend the control process by the communication application. Although there is a method of dividing an application for each control process, it is difficult to collect transmitted data. Therefore, when an application is divided for each control process, each application transmits data, but at this time, overhead increases due to a header of each data, a gap between frames, and the like. Therefore, when an application is divided for each control process, there is a problem that communication performance deteriorates due to such overhead. In view of the above, an object of the present invention is to solve the above-described problems and to prevent a reduction in communication performance while reducing the effort of developing a control computer that executes a plurality of control processes with different periods.

  In order to solve the above-described problems, the present invention is a control computer including one or more programs for controlling one or more control target devices, and a control command to the control target devices based on the program. Using the processing unit that outputs the value to the communication scheduler and the schedule information using the time slot, the control command value output from the processing unit is determined to be transmitted to each control target device via the network. A communication scheduler that transmits transmission data including a control command value to each control target device at the determined transmission time, and the communication scheduler uses the program to periodically transmit the control command value among the programs. The identification information of the control target device to be controlled, and the cycle when transmitting the control command value to the control target device When the input of the program management information shown is received, and the program information management unit stored in the program management information storage unit and the input of the control command value to the controlled device are received from the processing unit by the program, the control command value is A transmission time is determined so that transmission data including a control command value is transmitted at a cycle indicated by the transmission data management unit stored in the storage unit and the program management information, and the transmission time is recorded in the schedule information. The transmission time schedule unit that outputs a transmission instruction of the transmission data, and the control command value is read from the storage unit based on the transmission instruction output by the transmission time schedule unit, and includes the read control command value And a transmission unit that transmits transmission data.

  As described above, the communication scheduler of the control computer transmits the control command value to the control target device by the program for the periodic processing program (program for periodically outputting the control command value) provided in the control computer. The longest permissible period and the like when storing are stored in the program management information. Then, the communication scheduler determines a transmission schedule for transmitting the control command value so as to keep the longest allowable period indicated in the program management information. Based on the transmission schedule, transmission data including the control command value of the program is transmitted. In other words, the control computer transmits the transmission data including the control command value so as to satisfy the time constraint (the longest allowable period or the like) of the program that transmits the control command value. Therefore, it is not necessary to set a conditional branch for distinguishing the period of each periodic processing program in the communication application, and it is possible to reduce the effort of developing a control computer that executes control processing of one or a plurality of different periods. it can. Moreover, it is possible to prevent a decrease in communication performance by determining and transmitting a transmission schedule so that transmission data of a plurality of periodic processing programs are collected within a range permitted by time constraints.

  ADVANTAGE OF THE INVENTION According to this invention, the effort of development of the computer for control which performs the control processing of a several different period can be reduced. Further, it is possible to easily add a new control process (control process program), change the cycle of an existing control process, and the like. In addition, since the control computer transmits transmission data of a plurality of periodic processing programs at a time, it is possible to prevent a decrease in communication performance.

It is the figure which showed the hardware structural example of the computer for control of this Embodiment. It is the figure which showed the system configuration example using the computer for control of FIG. It is the figure which showed the structure of the communication scheduler of FIG. It is the figure which showed the structure of the program management part of FIG. It is the figure which showed the structural example of the program which operate | moves on the computer for control of FIG. It is the figure which showed the process sequence of the periodic process program of FIG. It is the figure which showed the process sequence of the periodic process program of FIG. It is the figure which showed the process sequence of the aperiodic processing program of FIG. It is the figure which showed the process sequence of the communication scheduler of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure explaining the example of a process sequence of the schedule change possibility determination part of FIG. It is the figure which illustrated allocation of the time slot in this Embodiment. It is the flowchart which showed the determination procedure of the schedule change possibility determination part with respect to the aperiodic processing program of this Embodiment. It is the figure which illustrated the transmission time schedule table (schedule information) of the time slot which the transmission time schedule part of this Embodiment manages. It is the figure which showed the hardware structural example of the computer for control of this Embodiment. FIG. 26 is a diagram illustrating a configuration example of a program operating on the control computer in FIG. 25. It is the figure which showed the hardware structural example of the computer for control of this Embodiment. It is the figure which showed the structure of the communication scheduler of FIG. It is the figure which showed the system configuration example using the computer for control of FIG.1, FIG.25, FIG.27.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described. FIG. 1 is a hardware configuration example of a control computer according to this embodiment. The control computer includes one or more programs for controlling the control target device, and the CPU (Central Processing Unit) 101 of the control computer stores the programs from the nonvolatile storage medium 109 to the memory 108. Transfer and execute. FIG. 1 shows a state where a program has been transferred to the memory 108. As this program, there are an OS (Operating System) including an interrupt handler and an application program that operates on the OS and controls the control target device 121. The communication scheduler 102 receives a communication request from the CPU 101 and communicates with the control network 122 using a LAN (Local Area Network) controller 103. As an implementation example of the communication scheduler 102, there are an IC (Integrated Circuit) such as an FPGA (Field Programmable Gate Array), a CPLD (Complex Programmable Logic Device), an ASIC (Application Specific Integrated Circuit), and a gate array.

  The LAN controller 103 is a transceiver IC that implements a communication function with the control network 122 (described later). As a communication standard provided by the LAN controller 103, an Ethernet (registered trademark) LAN controller, a combination of a MAC (Media Access Controller) chip and a PHYs (physical layer) chip, or a physical layer or a physical layer of a specific network specification and a data link IC etc. to process the layer.

  The memory 108 is a temporary storage area for the CPU 101 to operate, and stores an OS, application programs, and the like transferred from the nonvolatile storage medium 109.

  The non-volatile storage medium 109 is a storage medium such as a hard disk drive (HDD) or a flash memory, and is used for storing a program executed by the CPU 101 and storing a program execution result.

  The bus 110 connects the CPU 101, the memory 108, the nonvolatile storage medium 109, the communication scheduler 102, and the LAN controller 103, respectively. The bus 110 is a PCI (Peripheral Component Interconnect) bus, an ISA (Industrial Standard Architecture) bus, a PCI Express bus, a system bus, a memory bus, or the like.

  FIG. 2 is a system configuration example using the control computer 120. The control computer 120 is a hardware device that is connected to the control target device 121 via the control network 122 and controls the control target device 121. The control target device 121 is, for example, a servo amplifier or a servo motor. In FIG. 2, the network has a ring topology, but may be a topology such as a logical ring topology or a star topology.

  FIG. 3 shows a functional configuration diagram of the communication scheduler 102. The communication scheduler 102 includes a program management unit 130, a schedule change possibility determination unit 131, a datagram connection unit 132, a datagram decomposition unit 133, a time measurement unit 134, a transmission time scheduling unit 135, and a program wakeup unit 136. And a transmission unit 137 and a reception unit 138. A specific example of communication scheduling by the communication scheduler 102 will be described later.

  The program management unit 130 creates program information (program management information) for executing individual control processes, and stores the information in a storage unit (not shown) included in the communication scheduler 102. Since the program management unit 130 is necessary for each individual program (see FIG. 5), a plurality of program management units 130 may exist. The upper limit of the number of program management units 130 is limited by computer resources such as hardware, and it is necessary for the number of programs and control targets sufficient to construct a control system.

  The schedule change possibility determination unit 131 determines whether it is possible to add a new program, change the period of an existing program, or delete the registration of a program based on information such as time constraints and communication amount of each program. To do. For example, for all programs including a new program and a changed existing program, the program management information is referred to, and the total value of the data size of the control command value output from each program is determined as the communication processing throughput of the communication scheduler 102. Calculate the value divided by. Then, when this value is smaller than the shortest longest permissible period among the longest permissible periods of each program, it is determined that the time constraints of all the programs are satisfied. On the other hand, when this value is larger than the shortest longest permissible period among the longest permissible periods of each program, it is determined that the time constraints of all the programs are not satisfied. That is, the schedule change possibility determination unit 131 determines that this new program cannot be added or the existing program cannot be changed.

  The datagram concatenation unit 132 collects and concatenates data to be transmitted at the scheduled transmission time planned by the transmission time scheduling unit 135, transmits the data to the transmission unit 137, and updates the status flag of the status flag management unit 145 (described later). . In addition, the datagram concatenation unit 132 adds a header and trailer specific to the control network 122 (see FIG. 2), if necessary.

  Note that the order in which the datagram concatenation unit 132 concatenates the data of each program is not particularly limited as long as information for distinguishing each transmission data is added to the header unique to each transmission data. For example, the datagram concatenation unit 132 may concatenate the data of each program in the order of management in the program management unit 130. However, when the position of the transmission data has a unique meaning when transmitted on the control network 122, the transmission data is arranged at a position according to the specification of the control network 122. For example, when there is a restriction that the order in which the transmission data is located and the order in which the control target device 121 receives are the same, the transmission data is arranged according to the order of the control target device 121 to be received.

  The datagram decomposition unit 133 divides the data transmitted from the reception unit 138 into data for each program, and transmits the data to the datagram extraction unit 144 (described later) of the program management unit 130 of each program. In addition, the datagram decomposition unit 133 transmits the identifier of the program management unit 130 that has received the data to the program wake-up unit 136. That is, the control computer 120 transmits data indicating a control command value to the control target device 121 based on the program, and then receives data including a response to the control command value from the control target device 121 by the receiving unit 138. Receive. Here, there is a possibility that the received data includes responses to control command values of a plurality of programs. Therefore, the datagram decomposition unit 133 divides the received data for each program, and transmits (outputs) the data to the program management unit 130 of the program that performs processing related to the response. Further, the datagram decomposition unit 133 transmits the identifier of the program management unit 130 that has received the data to the program wakeup unit 136, so that the program wakeup unit 136 can determine which program should process the received data. You can be notified.

  The time measuring unit 134 has time measuring means and provides time information to each unit in the communication scheduler 102. This time information is used for measuring the elapsed time after execution of the control application and recording the occurrence time of various events. Note that the timer 134 may be replaced by a device such as a timer placed outside the communication scheduler 102.

  The transmission time schedule unit 135 extracts a program for extracting the scheduled transmission time and data to be linked from each program management unit 130 in consideration of time constraints such as the period of each program and setting information, and links the programs. . And the timing which transmits this data is determined. In addition, the transmission time schedule unit 135 obtains a period from the program management information by the program information management unit 142 of each program management unit 130 and notifies the datagram connection unit 132 of a program to be transmitted at the scheduled transmission time.

  The program wake-up unit 136 identifies which program the received data is based on the identifier of the program management unit 130 notified from the datagram decomposition unit 133, and wakes up the identified program. The wake-up method is exemplified by using an interrupt via the bus 110 (see FIG. 1). Wake-up can be performed at an arbitrary timing.

  The transmission unit 137 transmits the data transmitted from the datagram connection unit 132 to the LAN controller 103.

  The receiving unit 138 receives data from the LAN controller 103 and transmits the data to the datagram decomposition unit 133.

  FIG. 4 shows the configuration of the program management unit 130. The program management unit 130 inputs the transmission data of the program output from the CPU 101 (see FIG. 1) to the transmission data management unit 140. Also, the received data received from the control target device 121 (see FIG. 2) is output to the CPU 101 via the receiving unit 138 (see FIG. 3), the datagram decomposing unit 133, the datagram extracting unit 144, and the received data managing unit 141. To do. The program management unit 130 includes a program information management unit 142, a datagram generation unit 143, a datagram extraction unit 144, and a status flag management unit 145. The state flag management unit 145 updates the state flag. This status flag is stored in a predetermined area of the storage unit included in the communication scheduler 102.

  When the transmission data management unit 140 receives transmission data including a control command value output from the CPU 101 (see FIG. 1) based on the program, the transmission data management unit 140 temporarily stores the transmission data in a storage unit included in the communication scheduler 102. This transmission data includes a control command value and the like.

  The reception data management unit 141 outputs the reception data received from the control target device 121 to the CPU 101. The received data is data including a response result of the control target device 121 to the control command value indicated in the transmission data, for example.

  The program information management unit 142 manages the program included in the control computer 120 (see FIG. 1), control processing by the program, and program management information indicating the control target device 121 and the like. As this program management information, the identifier of the program, the identifier of the device to be controlled 121, the cycle when the control command value is sent by this program, the target transmission time, the longest allowable cycle, and the response processing when the data update is not in time within the cycle This is information indicating the corresponding processing at the time of changing the cycle, whether it is a cyclic program or a non-cyclic processing program, the priority between programs, the data position of the program in the transmission frame, and the like. The periodic program is a program for sending data to the control target device 121 at a predetermined period, and the aperiodic processing program is a program that does not need to periodically transmit data.

  When there is a transmission request from the CPU 101 (see FIG. 1), the datagram generation unit 143 converts and processes the transmission data into a format suitable for transmission. For example, as such processing, conversion to a format suitable for the specifications of the control network 122 (see FIG. 2) such as generation of a header and trailer specific to the communication protocol of the control network 122 is performed.

  In addition, when there is a data reception notification from the datagram decomposition unit 133, the datagram extraction unit 144 converts the received content into a format suitable for notification to the program. An example of such processing is removal of data headers and trailers.

  The status flag management unit 145 updates a status flag indicating the status of transmission data and reception data. For example, based on the program, the CPU 101 (see FIG. 1) has updated the transmission data of the transmission data management unit 140 but has not yet transmitted to the outside of the communication scheduler 102 (see FIG. 3). The transmission data of the unit 140 has been transmitted and the CPU 101 has not yet updated, the communication scheduler 102 has updated the reception data of the reception data management unit 141 and the CPU 101 has not yet acquired, and the CPU 101 has received the data management unit 141. The received data is already acquired, and the communication scheduler 102 has not yet received a packet from the outside. The program or transmission time schedule unit 135 inquires of the status flag management unit 145 about the status flag status. Thereby, for example, the transmission time schedule unit 135 can detect a case where the program could not update the transmission data within a predetermined period, and the program can check whether the reception data has been updated. It is possible to determine whether the received data is acquired or not.

  Next, FIG. 5 shows the configuration of a program that runs on the control computer 120. The programs operating on the control computer 120 include an OS 150, a device driver 151, a periodic processing program 152, an aperiodic processing program 153, an API (Application Program Interface) 154, a protocol stack 155, and a common setting program 156. In FIG. 5, the program located at the upper level uses the function provided by the lower level program. Note that each of the periodic processing programs 155 is a program for performing different processing. In FIG. 5, for the sake of explanation, programs for performing different processes are depicted as separate periodic process programs 152, but a plurality of different periodic processes may be executed by one program. The control computer 120 may not include the aperiodic processing program 153.

  The OS 150 provides basic functions such as program management and access to hardware. The OS is not necessarily required, but is preferably used because it provides basic functions such as general-purpose applications, use of existing software assets, and task management. The OS 150 is preferably a real-time OS that can execute task scheduling according to time constraints.

  The device driver 151 is a driver for accessing the communication scheduler 102 via the bus 110 using access means to the hardware provided by the OS 150. The device driver 151 may be a part of the OS 150.

  The periodic processing program 152 is an application program that runs on the control computer 120 and is periodically executed with time restrictions such as a period of transmission time in order to control, monitor, and diagnose the control target device 121. The periodic processing program 152 is used to access the communication scheduler 102 through the API 154 and the device driver 151, and to transmit / receive data for controlling, monitoring, and diagnosing the control target device 121. The control computer 120 is provided with one or more periodic processing programs 152.

  The aperiodic processing program 153 is a program for communication that does not have time constraints. Some control networks 122 (see FIG. 2) constituting this control system allow TCP / IP (Transmission Control Protocol / Internet Protocol) communication used on the Internet. In such a control network 122, data to be transmitted by TCP / IP communication is transmitted in conjunction with other data.

  The API 154 is a software interface for accessing the device driver 151, and is a program for providing a common access means to hardware by absorbing differences in hardware. The API 154 may be a part of the OS 150. The access means provided by the API 154 includes writing, reading, transmission, reception, setting, and the like for hardware. Specific examples of the API 154 include a library and middleware.

  The protocol stack 155 is a program for executing a transmission request by the aperiodic processing program 153, transfer of received contents to the aperiodic processing program 153, division of communication data, and reconfiguration. In general, the amount of communication in the control processing is small, and the amount of communication data in the periodic processing program 152 can be transmitted by one transmission / reception per command. However, the amount of communication in an application other than control does not fit in a single packet, and division and reconfiguration may be necessary. Also, retransmission processing for providing reliability and congestion control for adjusting the amount of communication on the network are performed. The protocol stack 155 is a program for performing these processes.

The common setting program 156 is a program for setting general functions of the communication scheduler 102.

  Next, FIG. 6 shows a processing procedure of the periodic processing program 152 in FIG. Here, when a new periodic processing program 152 is added in addition to the existing periodic processing program 152 of the control computer 120, the control computer 120 uses the new periodic processing program 152 in its own control computer 120. A case where it is determined whether or not the periodic processing program 120 can be executed will be described. First, based on the periodic processing program 152, the CPU 101 (see FIG. 1) inquires of the schedule change possibility determining unit 131 (see FIG. 3) of the communication scheduler 102 whether or not this periodic processing program 152 can be newly executed (S001). ). The details of the process for determining whether or not the periodic processing program 152 can be newly executed by the schedule change possibility determination unit 131 will be described later.

  If the schedule change possibility determination unit 131 determines that the periodic processing program 152 can be executed (Yes in S001), the periodic processing program 152 is information necessary for the periodic processing (and periodic communication) of the periodic processing program 152. Is set in the program management information of the program information management unit 142 (see FIG. 4) (S002). Information necessary for this periodic processing and periodic communication includes a program identifier, an identifier of the control target device 121 to which the periodic processing program 152 transmits a control instruction value, a period at which the control instruction value is transmitted, a target transmission time, and a longest allowable period. Corresponding process when data update is not completed within the period, corresponding process when changing the period, whether or not it is a periodic processing program or a non-periodic processing program, priority between programs included in the control computer 120, transmission data The data position of the program inside. In addition, the program information management unit 142 may set predetermined setting values for items that are not explicitly set by the periodic processing program 152. Note that if the schedule change possibility determination unit 131 determines that execution is not possible (No in S001), the periodic process ends.

  After S002, based on the periodic processing program 152, the CPU 101 calculates a control command value to be transmitted and determines transmission data (S003).

  Next, based on the periodic processing program 152, the CPU 101 transmits transmission data to the communication scheduler 102 (see FIG. 3) and enters a standby state (S004). Thereafter, when the receiving unit 138 of the communication scheduler 102 receives data from the control target device 121, the standby state is canceled (S005).

  After S005, the CPU 101 determines whether or not to end the periodic process program 152 (S006). If the process is not to be ended (No in S006), the procedure from S003 is repeated. If not (Yes in S006), the process is ended. Note that the end determination of S006 may be determined any time as long as it is within the periodically executed process, and may be executed during any of the steps from S003 to S005. The condition for determining the end depends on the determination of the developer and the specifications of the control system. For example, the CPU 101 determines that the transmission data has been terminated when the transmission data is transmitted a predetermined number of times or when the received data includes predetermined information.

  In addition to the procedure shown in FIG. 6, the data reception process may be executed independently of the periodic process. In this case, as shown in FIG. 7, after S002, the CPU 101 registers the content of the reception process based on the periodic process program 152 (S010). The content of this reception process is converted into a format suitable for periodic processing when received data is received, stored in a common area so that the received content can be acquired from periodic processing, And taking statistical values of received information. Further, based on the periodic processing program 152, the CPU 101 acquires reception information (S011). That is, the CPU 101 acquires received data from the memory 108 or the like before calculating the control command value. In addition, the CPU 101 appends to the received data a reception time, an identifier that is updated every time it is updated or acquired, etc. in order to identify when this received data is received data. Further, the reception data acquired here need not be one reception data, and may be a plurality of reception data. In the periodic process, more sophisticated control can be executed by using the received data at a plurality of times.

  Further, after S003 in FIG. 7, the CPU 101 transmits transmission data based on the periodic processing program 152 (S012). Next, the periodic processing program 152 enters a standby state (S013). Specific examples of the standby method include a POSIX (Portable Operating System Interface) sleep call and a system call that puts a process in a standby state. These system calls are provided by the OS 150.

  Thereafter, the CPU 101 is released from the standby state by the program wake-up unit 136 of the communication scheduler 102 based on the periodic processing program 152 (S014). After executing S014, the CPU 101 determines whether or not to end the periodic processing program 152 (S006). If the process is not to be ended (No in S006), the procedure from S011 is repeated. If not (Yes in S006), the process is ended. Note that the end determination of S006 may be determined any time as long as it is within a periodically executed process, and may be executed during any of the procedures from S011 to S014.

  FIG. 8 shows a processing procedure of the aperiodic processing program 153 (see FIG. 5). First, based on the aperiodic processing program 153, the CPU 101 (see FIG. 1) inquires of the schedule change possibility determination unit 131 of the communication scheduler 102 whether or not the aperiodic processing program 153 can be newly executed (S020). At this time, if the aperiodic processing program 153 has any restrictions such as the minimum guaranteed bandwidth and the longest allowable delay, the CPU 101 notifies the schedule change possibility determination unit 131 of this. If the schedule change possibility determination unit 131 determines that the non-periodic processing program can be executed (Yes in S020), the schedule change possibility determination unit 131 transmits or receives (S021). On the other hand, if the schedule change possibility determination unit 131 determines that the non-periodic processing program 153 cannot be executed (No in S020), the process ends.

  Next, the processing procedure of the communication scheduler 102 in the procedure shown in FIGS. 6, 7, and 8 will be described. In S001 of FIG. 6 and FIG. 7, and S020 of FIG. 8, the schedule of the communication scheduler 102 is changed to determine whether the CPU 101 (see FIG. 1) can execute the new periodic processing program 152 or the new aperiodic processing program 153. An inquiry is made to the possibility determination unit 131. The determination procedure of the schedule change possibility determination unit 131 for the periodic processing program 152 at this time will be described with reference to FIGS. Note that the programs A to K shown in FIGS. The data size indicates the maximum data size of control command value data transmitted by the periodic processing program 152. The unit of the data size in each figure is “B (byte)”.

  First, based on the periodic processing program 152, the CPU 101 sets the period of the control command value of the periodic processing program 152 and the data size (maximum data size) of the control command value to the schedule change possibility determination unit 131 (see FIG. 3). Apply (S040).

  Next, the schedule change possibility determination unit 131 determines whether there is a newly assignable computer resource such as the program management unit 130 (S041). If there is no computer resource (No in S041), the schedule change possibility determination unit 131 determines that the periodic processing program 152 cannot be executed (S057). The computer resource here is, for example, the storage capacity of the memory 108. On the other hand, if there is a computer resource (Yes in S041), the schedule change possibility determination unit 131 calculates a total value Sum1 of the data sizes of all currently executed programs (S042). For example, when the period and data size of each periodic processing program 152 are values as shown in FIG. 10, the schedule change possibility determination unit 131, as shown in FIG. (Byte) is calculated.

  After S042, the schedule change possibility determination unit 131 acquires the cycle μ1 of the program having the shortest cycle. That is, the shortest period μ1 is acquired (S043). For example, the schedule change possibility determination unit 131 acquires the shortest cycle (execution cycle) 20 μs among the cycles illustrated in FIG. 10 as μ1 (see FIG. 11).

  The schedule change possibility determination unit 131 calculates T1 obtained by dividing Sum1 calculated in S042 by the communication processing throughput of the communication scheduler 102 (S044). By calculating T1 like this, it is possible to know the communication processing time of the communication scheduler 102 when the cycles of all the periodic processing programs 152 overlap. For example, when the communication processing throughput of the communication scheduler is 100 Mbps, the schedule change possibility determination unit 131 calculates T1 = 305B / 100 Mbps = 24.4 μs.

  Returning to the description of FIG. Next, the schedule change possibility determination unit 131 determines whether the sum of T1 calculated in S044 and the safety factor is smaller than μ1 (S045). Here, if the sum of T1 calculated in S044 and the safety coefficient is smaller than μ1 (Yes in S045), it is determined that the periodic processing program 152 is executable (S056). On the other hand, if the sum of T1 calculated in S044 and the safety factor is μ1 or more (No in S045), there is room for execution of the periodic processing program 152, and the process proceeds to S046. For example, as shown in FIG. 11, when T1 = 24.4, safety factor = 0, and μ1 = 20μ, the sum of T1 and the safety factor is greater than or equal to μ1, so the process proceeds to S046.

  Returning to the description of FIG. Then, the schedule change possibility determination unit 131 groups all the periodic processing programs 152 currently being executed at a prime multiple cycle (S046). In other words, the schedule change possibility determination unit 131 groups all the periodic processing programs 152 in the same group for each periodic processing program 152 having a period that is a prime number times the time slot.

  For example, as shown in FIG. 12, the schedule change possibility determination unit 131 sets a program A having a 20 μs period and a program C having a 40 μs period as a 20 μs period group. Further, a program B having a cycle of 30 μs and a program I having a cycle of 90 μs are set as a 30 μs cycle group. Programs F, G, H, and E having a period of 70 μs are directly used as a 70 μs period group. Note that 60 μs is a common multiple of 20 μs and 30 μs, and 140 μs is a common multiple of 20 μs and 70 μs. Therefore, the schedule change possibility determination unit 131 keeps the program D having a period of 60 μs and the programs K and J having a period of 140 μs without being grouped. In other words, programs that can only be transmitted in that cycle are grouped as data for each cycle, and programs that have a plurality of selectable groups belonging to which cycle are put on hold without determining the group to which they belong. .

  Returning to the description of FIG. After grouping in this way, the schedule change possibility determination unit 131 adjusts the execution timing of the program (periodic processing program 152) in each group (S047). The adjustment of the program execution timing here does not exceed the data size (hereinafter referred to as Ts) that the schedule change possibility determination unit 131 can transmit per time slot, and the data size becomes as large as possible. In addition, it is performed by shifting the period of each period processing program 152 within the group. Specifically, the schedule change possibility determination unit 131 collects the same time slot from the periodic processing program 152 having a large data size, and shifts the periodic processing program 152 to another time slot when Ts is exceeded. When the cycle of the cycle processing program 152 is a common multiple of a prime multiple of different time slots, the schedule change possibility determination unit 131 incorporates Ts into a group in which the data size is as large as possible (however, Ts If so, join another group). In addition, the periodic processing program 152 whose data size is larger than Ts is assigned so as to use continuous time slots.

  For example, if the transmittable data size per time slot Ts = 100B, as shown in FIG. 13, the data size of the programs A and C in the 20 μs period group is 40B in total, so there is a margin of 60B. Therefore, the schedule change possibility determination unit 131 puts the held programs K and J having a period of 140 μs in this 20 μs period group, so that it becomes 100 B, and collects these data in the same time slot. The schedule change possibility determination unit 131 shifts the program D of 60 μs to another time slot of the 20 μs cycle group. Here, the reason why the programs K and J are selected as programs to be incorporated into the time slot of the 20 μs cycle group is that the data sizes of the programs K and J are larger than those of the program D. Next, the schedule change possibility determination unit 131 groups the programs B and I in the same time slot in a group with a period of 30 μs. Furthermore, programs F, G, and E having a period of 70 μs are collected. Note that the schedule change possibility determination unit 131 exceeds Ts (100 B) when the program H is collected, so the program H is shifted to another time slot of 70 μ cycles. Note that for a program whose data size (120B) alone exceeds Ts (for example, 100B), such as the program F of the 70 μs periodic group in FIG. 14, the schedule change possibility determination unit 131 in FIG. As shown, time slots are allocated as a plurality of consecutive chunks. That is, the program F is allocated across two consecutive time slots.

  Here, the schedule change possibility determination unit 131 sets μg as a value obtained by dividing the period in each group by the period of one time slot. For example, when the period of one time slot is 10 μs, the value of μg in the 20 μs period group is “2”. Next, the schedule change possibility determination unit 131 transmits the data of each periodic processing program 152 so that the number of types of time slots to be used is not more than μg in the group including the data of the program to be newly added. As a result of the adjustment, it is determined whether there is a time slot whose data size exceeds Ts (S048).

  Here, if there is a time slot whose data size exceeds Ts (Yes in S048), the schedule change possibility determination unit 131 determines that this periodic processing program 152 cannot be executed (S057). On the other hand, if there is no time slot whose data size exceeds Ts (No in S048), there is room for executing the program, and the process proceeds to S049.

  For example, as shown in FIG. 16, a 20 μs periodic group is μg = 2, a 30 μs periodic group is μg = 3, and a 70 μs periodic group is μg = 7. Here, in the 20 μs periodic group including the program to be newly added, there is no combination exceeding Ts even if the combination is μg = 2 (No in S048). Therefore, the process proceeds to S049.

  Returning to the description of FIG. The schedule change possibility determination unit 131 selects a combination of the periodic processing programs 152 when the data size is the largest in each of the remaining groups. Then, the schedule change possibility determination unit 131 calculates the sum value Sum2 of the data sizes of the combination and the combination of the program data when the data size is increased in the group including the newly added program (S049). ).

  For example, as shown in FIG. 16, the group having the largest data size in the group other than the 20 μs period group, that is, the 30 μs period group, is the combination of programs B and I, and the data size is 45B. The combination having the largest data size in the 70 μs periodic group is a combination of programs E, F, and G, and the data size is 100B. Therefore, the schedule change possibility determination unit 131 calculates Sum2 = 100B + 45B + 100B = 245B.

  Returning to the description of FIG. The schedule change possibility determination unit 131 determines whether Sum2 exceeds Ts (S050). If Sum2 does not exceed Ts (No in S050), schedule change possibility determination unit 131 adjusts the program execution timing based on this time slot to transmission time schedule unit 135 (see FIG. 3). Notification is made (S55). Then, the schedule change possibility determination unit 131 determines that the execution process of the periodic processing program 152 is possible (S056). Then, the schedule change possibility determination unit 131 newly assigns the program management unit 130 to the periodic processing program 152 (S058). Then, the process ends.

  On the other hand, when Sum2 exceeds Ts (Yes in S050), the schedule change possibility determination unit 131 changes the combination of programs constituting each time slot of each periodic group, thereby changing the longest data of the time slot. It is determined whether or not the total Sum2 can be reduced (S051).

  For example, as shown in FIG. 17, Sum2 = 245B calculated in S049 and this value exceeds Ts. Therefore, the process proceeds to S051, and the schedule change possibility determination unit 131 sets each time slot of each cycle group. It is determined whether or not the sum Sum2 of the longest data of the time slot can be reduced by changing the combination of the constituting programs (S051).

  Returning to the description of FIG. When it is determined in S051 that the total Sum2 of the longest data of the time slot can be reduced by changing the combination of programs constituting each time slot of each cycle group (Yes in S051), the schedule change possibility determination unit 131 Then, the program configuration of each time slot is changed (S052). Specifically, the schedule change possibility determination unit 131 shifts a program having a small data size to another time slot among a plurality of programs constituting a time slot having the maximum data size in the group, Reduce the maximum data size in the group. Then, the procedure of S049 is taken again.

  For example, as shown in FIG. 17, the schedule change possibility determination unit 131 has a periodic group in which a time slot having the maximum data size is composed of a plurality of programs. Therefore, the schedule change possibility determination unit 131 changes the data structure of the time slot having the maximum data size and decreases the maximum size. For example, in the schedule change possibility determination unit 131, the slot with the maximum data size in the 20 μs period group in FIG. 17 is a time slot composed of programs A, C, K, and J. Therefore, for example, the joule change possibility determination unit 131 moves the program J to the time slot of the program C as shown in FIG. Similarly, in FIG. 17, the slot with the maximum data size in the 30 μs period group is a time slot consisting of programs B and I. Therefore, as shown in FIG. 18, the schedule change possibility determination unit 131 moves the program B to another time slot for the time slots composed of the programs B and I. Similarly, in FIG. 17, the slot with the maximum data size in the 70 μs period group is a time slot composed of programs F, G, and E. Therefore, as shown in FIG. 18, the schedule change possibility determination unit 131 also moves the programs G and E to another time slot for the time slot composed of the programs F, G, and E, and A slot. In this way, the schedule change possibility determination unit 131 decreases the maximum size of the data in the time slot of each cycle group. And the process after S049 is repeated again. For example, as shown in FIG. 19, Sum2 = 60B + 30B + 40B = 130B is calculated. Here, since Sum2> Ts (100B) (Yes in S050), the process proceeds to S051.

  Returning to the description of FIG. When it is determined in S051 that the maximum size of the time slot cannot be reduced even if the combination of programs constituting each time slot of each cycle group is changed (No in S051), the schedule change possibility determination The unit 131 determines whether there is a program that can move to another cycle group among the programs of the cycle group. That is, the schedule change possibility determination unit 131 determines whether or not different grouping is possible for each program (S053). If different grouping is possible, the group is changed (S054), and the procedure from S047 is repeated.

  For example, as shown in FIG. 18, in the 20 μs period group, the time slots with the largest size are the time slots for programs A, D, and K and the time slots for programs C and J. Here, this 20 μs period group has “2” as μg (a value obtained by dividing the period in each group by the period of one time slot). Therefore, since the schedule change possibility determination unit 131 has already created two time slots, the maximum size of this time slot can be determined by moving one of the programs A, D, and K to another time slot. Can not be reduced. Therefore, the schedule change possibility determination unit 131 determines that the maximum size of the time slot cannot be reduced even if the combination of programs constituting each time slot of each periodic group is changed (No in S051). Then, it is determined whether different grouping is possible for each program (S053). Here, as shown in FIG. 19, the 20 μs period group also includes programs K and J having a period of 140 μs. Since the programs K and J having a period of 140 μs can be moved to a group having another period (70 μs period), the programs K and J are moved to the 70 μs period group as shown in FIG. In other words, when there is a program with a common multiple cycle in the maximum size time slot of each cycle group, the schedule change possibility determination unit 131 moves this program to a group with a common divisor cycle of this program cycle. Let By doing in this way, the schedule change possibility determination part 131 can reduce the maximum size of a time slot, protecting the microgram value determined for each period group. Then, returning again to S049 and calculating Sum2, as shown in FIG. 21, 30B + 30B + 40B = 100B. Since this value does not exceed Ts = 100B (No in S50), the process proceeds to S55. When the adjustment of the program execution timing is notified (S55), it is determined that the program can be executed (S56), and a new program is executed. The management unit 130 is assigned (S58).

  Returning to the description of FIG. On the other hand, in S053, if the schedule change possibility determination unit 131 cannot perform different grouping for each data (No in S053), it determines that the program cannot be executed (S057). In addition, the transmission time schedule unit 135 is notified that the execution timing needs to be adjusted in executing the periodic processing program 152 (S055). Then, the schedule change possibility determination unit 131 executes the processes after S056.

  By executing the processing as described above, the schedule change possibility determination unit 131 determines time slot allocation as illustrated in FIG. 22 for the programs A to K that are the periodic processing program 152, for example. For example, the time slot indicated by reference numeral 220 in FIG. 22 indicates that program A (10B), program D (20B), program I (30B), and program F (40B) are transmitted. That is, when the communication scheduler 102 reaches the transmission time of the time slot in the Ethernet (registered trademark) frame, transmission data including control command values of these programs is transmitted.

  Next, FIG. 23 shows a determination procedure of the schedule change possibility determination unit 131 (see FIG. 3) for the aperiodic processing program 153 (see FIG. 5).

  First, the schedule change possibility determination unit 131 determines whether there is a newly assignable computer resource such as the program management unit 130 (S041). If there is no computer resource (No in S041), it is determined that the program cannot be executed (S057).

  If there is a computer resource (Yes in S041), the schedule change possibility determination unit 131 reads the program management information of the program information management unit 142 and determines whether or not the aperiodic processing program 153 has a restriction (see FIG. S060). If there is no restriction (No in S060), the schedule change possibility determination unit 131 refers to the transmission time schedule table (time slot table) 160 in the transmission time schedule unit 135 to determine whether there is a schedule available. Is confirmed (S061).

  FIG. 24 is a diagram illustrating a time slot transmission time schedule table (time slot table) 160 managed by the transmission time schedule unit 135. The transmission time schedule information is stored in the storage unit of the communication scheduler 102. In the time slot table 160, the horizontal axis represents time slots from the current time to a predetermined slot later in time series, and the vertical axis represents the data size per time slot. In response to the inquiry from the schedule change possibility determination unit 131, the transmission time schedule unit 135 checks whether there is a time slot in which data is not yet filled in the time slot table 160 as shown in FIG. To do. That is, the schedule change possibility determination unit 131 determines that there is an empty schedule if there is an empty time slot for transmitting data of the non-periodic processing program 153 in the time slot table 160.

  If there is no space in the schedule in S061 of FIG. 23 (No in S061), the schedule change possibility determination unit 131 determines that the aperiodic processing program 153 cannot be executed (S057). If the schedule change possibility determination unit 131 determines that the aperiodic processing program 153 can be used if it waits for a predetermined time, it is recorded in a log, and even if it waits for the predetermined time. Good.

  If there is an empty schedule in the transmission time schedule unit 135 in S061 (Yes in S061), the schedule change possibility determination unit 131 determines that the non-periodic processing program 153 can be executed (S056). On the other hand, if there is a restriction on the aperiodic processing program 153 in S060 (Yes in S060), the schedule change possibility determination unit 131 determines whether or not the restriction on the aperiodic processing program 153 is a guarantee of the minimum communication bandwidth ( S062). If the restriction is the guarantee of the minimum communication band (Yes in S062), the transmission time schedule unit 135 is checked whether the band can be guaranteed (S063). That is, the schedule change possibility determination unit 131 checks whether or not the transmission time schedule unit 135 has a schedule vacancy that can guarantee the minimum communication bandwidth.

  For example, when the minimum communication bandwidth of the non-periodic processing program 153 is 5 B / s, the transmission time schedule unit 135 determines whether or not there is a 5 B space in the time slot for one second after the current schedule in FIG. And the confirmation result is returned to the schedule change possibility determination unit 131.

  Here, if there is an empty schedule (Yes in S063), the schedule change possibility determination unit 131 determines that the aperiodic processing program 153 can be executed (S056). Then, the program information management unit 142 is requested to update the program management information (S066). That is, the program information management unit 142 is instructed to add information on the aperiodic processing program 153. On the other hand, if there is no available schedule (No in S063), the schedule change possibility determination unit 131 determines that the non-periodic processing program 153 cannot be executed (S057).

  In S062, if the restriction of the non-periodic processing program 153 is not the guarantee of the minimum communication bandwidth (No in S062), the schedule change possibility determination unit 131 determines whether or not the restriction of the non-periodic processing program 153 is the longest allowable delay. (S064). If the constraint is the longest allowable delay (Yes in S064), the CPU 101 applies the data size to the schedule change possibility determination unit 131 based on the non-periodic processing program 153, and sends the longest allowable delay to the transmission time schedule unit 135. It is confirmed whether or not the delay condition can be guaranteed (S065).

  For example, when the longest allowable delay of the non-periodic processing program 153 is 10 μs and the data size is 10 B, the transmission time schedule unit 135 sets the time from the present to 10 μs ahead in the time slot table 160 of FIG. It is checked whether or not there is a time slot with 10B of free slots. Then, the confirmation result is returned to the schedule change possibility determination unit 131.

  Here, when it is determined that the longest allowable delay can be guaranteed (Yes in S065), the schedule change possibility determination unit 131 determines that the aperiodic processing program 153 can be executed (S056). If it cannot be guaranteed (No in S065), the schedule change possibility determination unit 131 determines that the aperiodic processing program 153 cannot be executed (S057). In S064, if the constraint of the aperiodic processing program 153 is not the longest allowable delay (No in S064), the schedule change possibility determination unit 131 determines that the aperiodic processing program 153 cannot be executed (S066). . However, if other constraint determination methods are prepared, the determination can be made sequentially.

  Based on the periodic processing program 152, the CPU 101 uses the program information management unit 142 of the program management unit 130 as the program management information in step S <b> 002 of FIG. 6 and FIG. 7. Set. In step S004, transmission data is set in the transmission data management unit 140. Specifically, when the transmission data management unit 140 is set for the first time, this is notified to the transmission time scheduling unit 135, and the transmission time scheduling unit 135 updates the future transmission schedule. The update of the transmission schedule of the transmission time schedule unit 135 will be described.

  The transmission time schedule unit 135 manages the data transmission schedule based on the time slot. As illustrated in FIG. 24, the transmission time schedule unit 135 transmits transmission data in which data is concatenated by the datagram concatenation unit 132 for each time slot. The width of this time slot is determined in consideration of the processing time of the communication scheduler 102 required to transmit a packet of an appropriate size and the control processing request cycle.

  For example, when the processing time of the communication scheduler 102 necessary for transmitting a 100B packet is 10 μs, the width of the time slot is 10 μs. At this time, the request period of the control process is also a multiple of 10 μs. Further, when transmitting a packet having a data size of 100 B or more, it is necessary to perform processing such as occupying a plurality of time slots. The width of the time slot may be, for example, a width that allows the schedule change possibility determination unit 131 to easily determine the schedule, or if there is a restriction on the control system such as not transmitting a packet of 500 B or more, a width that meets the restriction It may be.

  Here, the time slot management method of the transmission time schedule unit 135 will be described using FIG. 24 again. In the time slot table 160 of FIG. 24, the horizontal axis represents time slots from the current time to a predetermined slot later in time series, and the vertical axis represents the data size that can be processed by the communication scheduler 102 per time slot. In the transmission time schedule table 160, the CPU 101 slides the pointer indicating the current time on the horizontal axis as the time slot time elapses, and repeats the process of returning to the head when reaching the end.

  The transmission time schedule unit 135 writes the scheduled transmission time of the program determined by the schedule change possibility determination unit 131 and its data size in the time slot table 160. At this time, the program schedule is incorporated into the same time slot as much as possible within the range satisfying the restrictions given to each program. However, when the schedule change possibility determination unit 131 determines that it is necessary to shift the time slot as shown in S046 to S053 in FIG. 9, the time slot is shifted.

  Further, in the case of the periodic processing program 152 having a period larger than the width of the horizontal axis of the time slot table 160, the number of remaining time slots until transmission is individually managed, and the number of remaining time slots as time passes. Decrease by one. Then, when the number of time slots becomes 0, the data of this periodic processing program 152 is transmitted. Thereafter, the number of time slots is initialized to a value for the period.

  Further, based on the periodic processing program 152, the CPU 101 can notify the transmission time scheduling unit 135 of transmission data within the period of the periodic processing program 152 indicated in the program management information in S002 of FIGS. You can set the behavior when there is no. Examples of such settings include transmitting previous command values as the same data, stopping transmission, presenting an error to the user at the time of a transmission request, delaying transmission until a request comes. In addition, the number of transmission delays for such a period, the time, and the like are recorded, and the user can use this information for diagnosis of the control computer 120 and the like.

  7 may be executed at an appropriate timing in accordance with the transmission timing based on the periodic processing program 152.

  6, 7, and 8, the program management unit 130 is released, and the transmission time schedule unit 135 deletes the schedules related to the periodic processing program 152 and the aperiodic processing program 153.

  When the period of the process is changed during the execution of the period processing program 152, the CPU 101 inquires of the schedule change possibility determination unit 131 of the communication scheduler 102 based on the period processing program 152 whether or not the period can be changed. . Then, when it is determined that the cycle can be changed, the processing after S002 in FIG. 6 is executed. Whether or not the cycle of the cycle processing program 152 can be changed is determined by the same processing as the processing shown in FIG. In other words, the schedule change possibility determination unit 131 may receive an application for the changed cycle and the maximum data size for the cycle processing program 152 to be changed (S040), and execute the processing after S041.

  According to such a control computer 120, the CPU 101 does not need to synchronize with other periodic processing programs 152 based on the periodic processing program 152, and can transmit and receive data at an arbitrary timing. Further, the control computer 120 can implement control processing and communication processing independently of the periodic processing program 152 and the non-periodic processing program 153. With these features, the dependency of the periodic processing program 152 and the non-periodic processing program 153 in the control computer 120 can be lowered, and reusability, maintainability, expandability, and flexibility can be improved as software. In other words, the control computer 120 can easily change or expand an existing system, and can be easily reused even when the periodic processing program 152 for a specific control target device 121 is used in another control system. It is.

  In addition, the control computer 120 can concatenate data and transmit them collectively in consideration of the restrictions of the periodic processing program 152 and the non-periodic processing program 153. Therefore, even when the same amount of data is transmitted, the number of transmission packets can be reduced, and overhead for processing common parts such as headers and trailers can be reduced. For example, in Ethernet (registered trademark), there is an overhead associated with communication of an 8B preamble, a 14B header, a 4B FCS (Frame Check Sequence), and a 96-bit time interframe gap. By reducing these overheads, the shortest reachable cycle can be shortened, and the control performance of the controlled object can be improved.

  Note that the function of the communication scheduler 102 of the control computer 120 may be realized by executing the program of the control computer 120. As shown in FIG. 25, such a control computer 120 does not include the communication scheduler 102 of the control computer 120. The configuration of a program that runs on this control computer 120 is shown in FIG.

  The communication scheduler 170 in FIG. 26 is a program that runs on the CPU 101 and realizes the same functions as the communication scheduler 102 described above. The communication scheduler 170 receives a communication request from the periodic processing program 152 and the protocol stack 155, accesses the LAN controller 103 via the device driver 151, and communicates with the control network 122 (see FIG. 2). The communication scheduler 170 is, for example, middleware, a server program, a kernel module, or the like.

  The control computer 120 and the control target device 121 may be connected by a network other than the LAN. In this case, as shown in FIG. 27, the communication scheduler 180 of the control computer 120 further includes a communication controller 181 for connecting to this control network.

  In addition, as shown in FIG. 28, the communication scheduler 180 can use various information for the control computer 120 to use the control network (for example, the time that the control computer 120 can be used). A network protocol information management unit 190 that stores information regarding packets that can be transmitted and received during a long period of time. Then, the transmission time schedule unit 135 acquires information on the use of the control network from the network protocol information management unit 190, and refers to this information to perform transmission data scheduling.

  Further, as shown in FIG. 29, the control computer 120 may be connected to the control target device 121 by a bus network. In addition, as shown in FIG. 29, the control system may control a plurality of control target devices 121 by a plurality of control computers 120. In the case of a control system including a plurality of control computers 120 as described above, scheduling is performed such that the control computers 120 synchronize with respect to the timing at which transmission data is transmitted to each other.

  Further, the transmission unit 137 (see FIG. 3) of the control computer 120 has been described as an example of transmitting an Ethernet (registered trademark) frame. May be transmitted.

102, 170, 180 Communication scheduler 103 LAN controller 108 Memory 109 Non-volatile storage medium 110 Bus 120 Control computer 121 Control target device 122 Control network 130 Program management unit 131 Schedule change possibility determination unit 132 Datagram concatenation unit 133 Datagram Decomposition unit 134 Timing unit 135 Transmission time schedule unit 136 Program wake-up unit 137 Transmission unit 138 Reception unit 140 Transmission data management unit 141 Reception data management unit 142 Program information management unit 143 Datagram generation unit 144 Datagram extraction unit 145 Status flag management unit 151 Device Driver 152 Periodic Processing Program 153 Aperiodic Processing Program 154 API
155 Protocol stack 156 Common setting program 181 Communication controller 190 Network protocol information management unit

Claims (8)

A control computer comprising one or more programs for controlling one or more controlled devices,
Based on the program, a processing unit that outputs a control command value to the control target device to a communication scheduler;
Using the schedule information using the time slot, the control command value output from the processing unit is determined to be transmitted to each control target device via the network, and the control command value is determined at the determined transmission time. The communication scheduler for transmitting transmission data including a value to each of the control target devices,
The communication scheduler is
Among the programs, for the program that periodically transmits the control command value, the identification information of the control target device to be controlled by the program and the cycle when transmitting the control command value to the control target device are shown. A program information management unit that receives input of program management information and stores it in the program management information storage unit;
A transmission data management unit for storing the control command value in the storage unit when receiving an input of a control command value to the control target device from the processing unit by the program;
The transmission time is determined so as to transmit the transmission data including the control command value in the cycle indicated by the program management information, the transmission time is recorded in the schedule information, and when the transmission time is reached, the transmission data A transmission time schedule part that outputs a transmission instruction of
A control unit comprising: a transmission unit that reads out the control command value from the storage unit based on a transmission instruction output by the transmission time schedule unit, and transmits the transmission data including the read control command value. Calculator. The communication scheduler is
A receiving unit that receives reception data that is a response to the control command value from the control target device;
A program wake-up unit that wakes up the program that outputs the control command value when the received data is received;
The processor is
Based on the wake-up program, the next control command value is determined based on the response indicated in the received data, and based on the wake-up instruction of the program, the determined control command value is output to the communication scheduler. The control computer according to claim 1. The program management information is
Further including the maximum value of the data size of the control command value output from each of the programs
The communication scheduler is
For each program being executed by the processing unit, referring to the program management information, a value obtained by dividing the total value of the data size of the control command value output from each program by the communication processing throughput of the communication scheduler is A schedule change possibility determination unit that determines that the time constraint of each program is satisfied when the period of each of the programs is smaller than the shortest period,
The transmission time schedule part is
2. The control according to claim 1, wherein when the schedule change possibility determination unit determines that the time constraint of each program is satisfied, a transmission time of transmission data including the control command value is determined. Calculator. The communication scheduler is
When it is determined by the schedule change possibility determination unit that the time constraint of each program being executed is satisfied, each of the programs in which the cycle of the control command value of the program is a prime number multiple A datagram concatenating unit for creating the transmission data in which the control command values are summarized below the maximum data size that can be transmitted per one time slot,
The transmitter is
The control computer according to claim 1, wherein the created transmission data is transmitted at the output transmission time. The transmission time schedule part is
Among the programs, the total data size of the control command values of each program whose control command value cycle is a prime number multiple exceeds the maximum data size that can be transmitted per one time slot. When
The transmission time schedule unit divides the control command value group of the program into a group of control command values equal to or less than the maximum data size, and assigns the divided group of control command values to different time slots. The control computer according to claim 4. The transmitter is
3. The control computer according to claim 2, wherein transmission of transmission data to the control target device via the network and reception of reception data from the control target device are performed in an Ethernet (registered trademark) frame. . The transmitter is
The control computer according to claim 2, wherein transmission data is transmitted to the control target device via the network and reception data is received from the control target device in a time-sharing manner.   The control system according to claim 1, wherein a topology of a network connecting the control computer and the control target device is a ring topology.

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