Control device and control system

Abstract

To realize a technique for effectively utilizing a transmission band in a control system that synchronizes the times of a control device and controls a controlled device.SOLUTION: A control device included in a control system that executes control over a controlled device using a time-synchronized control device includes: a communication unit that transmits and receives information on a control device included in the control system; an information collection unit that collects network connection information on the control system via the communication unit; an information storage unit that stores the network connection information; a calculation condition storage unit that stores a calculation condition used to calculate a frame transmission time related to a time at which the control device transmits a frame; a transmission time calculation unit that calculates the frame transmission time on the basis of the collected network connection information and the calculation condition; and a distribution unit that distributes the frame transmission time.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a control device and a control system.

Background Art

[0002] Control systems are installed in various social infrastructure systems. Through the automation and efficiency improvement of the control system by a plurality of control devices that execute arithmetic processing, the social infrastructure system has been automated and made more efficient.

[0003] A control device that constitutes such a control system acquires acquisition information such as various state quantities from detection devices such as sensors installed in the field, and the central arithmetic processing unit of the control device executes arithmetic processing. Then, the control device outputs a control command to operating devices such as motors and actuators installed in the field, and controls the operating devices that are the control targets in real time.

[0004] Further, for example, in a control system in a large-scale social infrastructure system, a plurality of control devices are connected via a common network to form a distributed control system. The distributed control system executes arithmetic processing based on acquisition information acquired from a plurality of detection devices installed in a vast field. Such a distributed control system is considered to execute highly efficient control by sharing the roles of a control device that executes arithmetic processing and a control device that outputs a control command, for example.

[0005] One method for synchronizing data between control units in a distributed control system is the shared memory method. In the shared memory method, each control unit constituting the distributed control system has a shared memory implemented in its own memory, and each control unit transmits the data stored in the shared memory to other control units. This allows data to be shared between control units, reducing the communication load between them. In this case, the control units synchronize their time, transmit the data stored in the shared memory at the same time, and output control commands to the controlled object, enabling high-precision real-time control, such as simultaneous processing of multiple processes or processing at desired times in a time series. Therefore, information for time synchronization is exchanged, and each control unit synchronizes its time.

[0006] As background technology in this field, for example, there is Japanese Patent Publication No. 2019-41264 (Patent Document 1). Patent Document 1 describes a communication system in a wireless multi-hop network that compares the number of hops to a base station with that of adjacent nodes and adjusts the transmission timing of the time slot assigned to the station. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-41264 [Overview of the project] [Problems that the invention aims to solve]

[0008] The communication system described in Patent Document 1 compares the number of hops from the base station of the local node and the adjacent node, adjusts the transmission timing by utilizing the available slots allocated to the adjacent node, and avoids collisions with time slots allocated to the preceding and succeeding nodes. However, Patent Document 1 does not appear to describe any technology for effectively utilizing the transmission bandwidth. Therefore, there are challenges in effectively utilizing the transmission bandwidth. [Means for solving the problem]

[0009] A typical example of the invention disclosed in this application is as follows: The control device is included in a control system that performs control on a controlled device using a time-synchronized control device. The communication unit transmits and receives information about the control device included in the control system. The information collection unit collects network connection information of the control system via the communication unit. The information storage unit stores the network connection information. The calculation condition storage unit stores calculation conditions used to calculate the frame transmission time, which relates to the time when the control device transmits a frame. The transmission time calculation unit calculates the frame transmission time based on the collected network connection information and calculation conditions. The distribution unit distributes the frame transmission time. Another example is as follows: The control device is included in a control system that performs control on a controlled device using a time-synchronized control device. The communication unit transmits and receives information about the control device included in the control system. The communication unit receives the frame transmission time, which relates to the time when the distributed frame is transmitted, and transmits the frame according to the frame transmission time.

[0010] A representative example of the invention disclosed in this application is as follows: The control system synchronizes the time of the control device and performs control on the controlled device. The control system comprises a first control device and a second control device. The first control device comprises a communication unit, an information collection unit, an information storage unit, a calculation condition storage unit, a transmission time calculation unit, and a distribution unit. In this first control device, the communication unit transmits and receives information about the control devices included in the control system. The information collection unit collects network connection information of the control system via the communication unit. The information storage unit stores the network connection information. The calculation condition storage unit stores calculation conditions used to calculate the frame transmission time, which relates to the time when the control device transmits a frame. The transmission time calculation unit calculates the frame transmission time based on the collected network connection information and calculation conditions. The distribution unit distributes the frame transmission time. The second control device comprises a communication unit. In this second control device, the communication unit receives the frame transmission time distributed from the first control device and transmits a frame according to the frame transmission time. [Effects of the Invention]

[0011] According to one aspect of the present invention, by distributing appropriate frame transmission times, effective utilization of transmission bandwidth can be achieved in a control system. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows an example configuration of the control system according to the first embodiment. [Figure 2] This is an explanatory diagram illustrating an example of the configuration of a control device. [Figure 3] This figure shows an example of the functional configuration of a control device. [Figure 4] This figure shows an example of another functional configuration of the control device. [Figure 5] This is a timing chart showing an example of the frame transmission timing of a control device. [Figure 6]It is a diagram showing an example of the range for determining the transmission timing of the control device. [Figure 7] It is a diagram showing an example of the content of the transmission timing information of the control device. [Figure 8] It is a timing chart showing an example of the operation timing of the control device. [Figure 9] It is a diagram showing a configuration example of the control system according to the second embodiment. [Figure 10] It is a timing chart showing an example of the transmission timing of the frame of the control device. [Figure 11] It is an explanatory diagram explaining an example in which the control device is applied to a steel system according to the third embodiment. [Figure 12] It is an explanatory diagram explaining an example in which the control device is applied to a FA system according to the fourth embodiment.

Mode for Carrying Out the Invention

[0017] The control devices (100, 101, 102) output control commands (control data such as control signals and command values) to operating devices (controlled devices that are the control targets), such as motor A 11, motor B 14, and actuator A 12 installed in the field, and control the operating devices in real time. That is, the distributed control system is composed of control devices that execute control over the operating devices.

[0018] The control networks (1 to 5) to which each device is connected are networks that perform data communication using a communication method configured by an IEEE standard called, for example, TSN (Time Sensitive Network), or industrial networks standardized by IEC61784 or the like. By using time slot communication based on time division control, it is a network that improves the time certainty in communication delay between control devices. Also, as the connection form, it may be a connection by a wired cable or a wireless connection such as a mobile phone network or a wireless LAN.

[0019] Sensor A 10, motor A 11, and actuator A 12 are connected to the control device 100 via the field network 20. Similarly, sensor B 13 and motor B 14 are connected to the control device 101 via the field network 21, and sensors C 15 and C 16 are connected to the control device 102 via the field network 22.

[0020] The field networks (20, 21, 22) may be, for example, networks defined by IEC 61158. Alternatively, the control device 100 and sensors A10 and actuator A12 may be directly connected to input and output digital and analog signals. In this case, the control device 100 and sensors A10 and actuator A12 are connected by multiple input / output signal lines.

[0021] Control device 100 shares the sensing data input from sensor A10 with control devices 101 and 102 as shared data via control network 1. Similarly, control device 101 shares the sensing data input from sensor B13 with control devices 100 and 102 as shared data via control network 2, and control device 102 receives input from sensors C15 and C16 and shares the shared data with control devices 100 and 101 via control network 4.

[0022] In this example, the control device 102 calculates control commands (command values) for, for example, motor A11, actuator A12, and motor B14 from the shared input data, and shares these control commands with the control devices 100 and 101. Meanwhile, the control device 100 controls motor A11 and actuator A12 using the shared control commands, and similarly, the control device 101 controls motor B14 using the shared control commands.

[0023] Sensors A10, B13, C15, and C16, which are installed in the field, are detection devices that detect and acquire information, which consists of various state quantities such as flow rate, temperature, pressure, tension, and rotational speed.

[0024] Next, the configuration of the control device 100 will be described. Figure 2 is an explanatory diagram illustrating an example of the configuration of the control device 100 according to the first embodiment.

[0025] The control device 100 includes a CPU 1001, a memory 1002, a communication control unit 1003, an interface unit 1004, a non-volatile storage medium 1005, a bus 1006, and an input / output unit 1007.

[0026] Although the control device 100 will be described here, the control devices 101 and 102 have the same basic configuration as control device 100.

[0027] The CPU 1001 is a central processing unit that controls the operation of each component of the control device 100.

[0028] Memory 1002 contains a temporary storage area used when the CPU 1001 is operating, and stores, for example, the operating system (hereinafter referred to as OS) and application programs transferred from the non-volatile storage medium 1005.

[0029] Furthermore, the memory 1002 is provided with an area for storing program A which operates on each control device, an area for storing retained information A acquired by each control device (information acquired by each control device from detection devices and controlled objects), and an area for storing shared data (acquired information and control commands acquired by control A) which is shared among the control devices via the control network 1.

[0030] The communication control unit 1003 performs data communication with the control devices 101 and 102 via the control network 1. For data communication, for example, the MAC (Media Access Control) layer functionality of the IEEE 802.3 standard may be implemented. In accordance with this standard, a frame is generated with destination information and error correction codes added to the transmitted and received data. Examples of implementations for the communication control unit 1003 include an IC (Integrated Circuit), FPGA (Field Programmable Gate Array), and gate array. Furthermore, the communication control unit 1003 may be integrated with the CPU 1001.

[0031] Furthermore, the communication control unit 1003 has the function of executing a time synchronization protocol by exchanging time synchronization packets using the network. In other words, the communication control unit 1003 has functions such as timing when sending and receiving time synchronization packets, and setting and adding correction values ​​to time synchronization packets. Such time synchronization protocols used include IEEE1588, IEEE802.1AS, NTP, and SNTP. In addition, the communication control unit 1003 has a time management function based on the synchronization time and communicates synchronization time information to the control devices 101 and 102.

[0032] The interface unit 1004 transmits and receives data to and from the control network 1. The interface unit 1004 implements, for example, the physical layer functionality of IEEE 802.3. Note that the interface unit 1004 may also be included in the communication control unit 1003.

[0033] In Figure 2, the control device 100 has one communication control unit 1003 and one interface unit 1004, but it may have multiple communication control units 1003 and multiple interface units 1004.

[0034] The non-volatile storage medium 1005 is an information storage medium, and stores, for example, the OS, applications, device drivers, programs that operate the CPU 1001, and the results of program execution.

[0035] The non-volatile storage medium 1005 can be comprised of, for example, a hard disk drive, a solid-state drive, or flash memory. Alternatively, the non-volatile storage medium 1005 may be comprised of an easily removable external storage medium such as a USB memory stick or a solid-state drive.

[0036] The input / output unit 1007 is an input / output interface that acquires information from a device connected to the control device 100, such as sensor A10, and controls motor A11 and actuator A12. The input / output unit 1007 implements, for example, the functions of the various field networks 20 described above, as well as digital input / output functions and analog input / output functions. Although Figure 2 shows one signal line from the input / output unit 1007, there may be multiple signal lines.

[0037] Bus 1006 connects the CPU 1001, memory 1002, communication control unit 1003, non-volatile storage medium 1005, and input / output unit 1007 in a communication-enabled manner.

[0038] Next, the functional configuration of the control device will be described. Figure 3 is a diagram showing an example of the functional configuration of the control device 100 according to the first embodiment.

[0039] The control device shown in Figure 3 (a control device that determines the frame transmission time related to the time when the control device transmits a frame, and is sometimes called the first control device) includes a communication unit 301, an information collection unit 302, an information storage unit 303, a calculation condition setting unit 304, a transmission timing calculation unit 305, and a distribution unit 306. It also includes a calculation condition storage unit (not shown) that stores the calculation conditions used to calculate the frame transmission time in a non-volatile storage medium 1005.

[0040] The communication unit 301 is a functional unit that connects to the control network 1 and communicates based on the communication protocol of the control network 1. For example, the communication unit 301 consists of software running on the CPU 1001, a communication control unit 1003, and an interface unit 1004. In other words, the communication unit 301 transmits communication frames related to its own control unit to other control units via the control network 1 and receives information related to other control units from other control units. The communication unit 301 also transmits information acquired by its own control unit and receives information acquired by other control units.

[0041] The information gathering unit 302 collects network information such as the connection status of each of the aforementioned control devices and network switches. Network information includes, for example, the network topology of the entire control system, the time synchronization error between each control device and the time master, the propagation delay time between each control device, the transfer period, and the transfer order.

[0042] The information storage unit 303 stores the network information collected by the information collection unit 302 and provides it to the transmission timing calculation unit 305 as network information.

[0043] The calculation condition setting unit 304 sets the calculation conditions for calculating the transmission timing to the transmission timing calculation unit.

[0044] The transmission timing calculation unit 305 calculates the transmission timing of the frame to be transmitted based on the information and settings from the information collection unit 302 and the calculation condition setting unit 304.

[0045] The distribution unit 306 distributes the transmission timing information calculated by the transmission timing calculation unit 305 to each control device.

[0046] Next, an example of another functional configuration of the control device according to the first embodiment will be described. Figure 4 is a diagram showing the functional configuration of the control device 101 according to the first embodiment.

[0047] The control device shown in Figure 4 (a control device that transmits frames according to the transmitted frame time, sometimes referred to as the second control device) includes a communication unit 401, a time synchronization unit 402, a frame buffer 403, a transmission timing information acquisition unit 404, a transmission timing adjustment unit 405, and a transmission data generation unit 406. The communication unit 401 is the same as the functional unit of the control device 100 shown in Figure 3 above.

[0048] The time synchronization unit 402 executes a time synchronization procedure. The time synchronization protocols executed by the time synchronization unit 402 include the aforementioned IEEE1588, IEEE802.1AS, NTP, and SNTP. The time synchronization unit 402 uses the time measured by the communication unit 401 when transmitting or receiving time synchronization packets to synchronize with the control devices 100 and 102. In other words, the time synchronization unit 402 synchronizes with the clock master, which serves as the time reference among the other control devices that constitute the distributed control system. The clock master is selected from among the connected control devices according to a predetermined procedure.

[0049] The time synchronization unit 402 may be implemented as an application running on the CPU 1001, or the communication control unit 1003 may be implemented as a hardware logic circuit using an IC or FPGA. Alternatively, the time synchronization unit 402 may be configured using both the software of the CPU 1001 and the hardware of the communication control unit 1003. In this case, the functions for measuring the transmission and reception timing of time synchronization packets and generating the time synchronization packet format may be handled by the communication control unit 1003.

[0050] The frame buffer 403 stores frames to be transmitted and received by the communication unit 401 via the control network 2.

[0051] The transmission timing information acquisition unit 404 extracts, acquires, and stores the transmission timing information received from the frame buffer 403 via the communication unit.

[0052] The transmission timing information adjustment unit 405 provides the frame buffer 403 with the transmission time of the transmission frame stored in the frame buffer 403, according to the transmission timing information held in the transmission timing information acquisition unit 404.

[0053] The transmission data generation unit 406 generates data to be transmitted to other control devices and stores it in the frame buffer 403. The transmission data generation unit 406 generates data that includes, for example, sensing data from other control devices and sensing data acquired by its own control device.

[0054] The frame buffer 403 outputs the transmission data from the transmission data generation unit 406 to the communication unit 401 according to the transmission timing of the transmission timing adjustment unit 405, and the frame is transmitted from the communication unit 401 at the specified transmission timing.

[0055] Next, the operating timing of the control device according to the first embodiment will be described. Figure 5 is a timing chart showing an example of the operating timing of the control device according to the first embodiment, and it shows the state in which the control system performs processing based on a predetermined shared period.

[0056] In Figure 5, the part indicated by the symbol a represents the transmission time predetermined within the shared cycle of the frame that transmits the shared data of control devices 100, 101, and 102.

[0057] The control device 100 is scheduled to transmit frame A at time t1, and when the data sharing time for control device 100 ends, control device 101 will transmit frame B at time t2, and when the data sharing time for control device 101 ends, control device 102 will transmit frame C at time t3. These frames are set as close together as possible to make effective use of the transmission bandwidth (i.e., the range indicated by code TB in Figure 5).

[0058] In Figure 5, the part indicated by the symbol b represents the transmission timing of each control device according to this embodiment. Figure (1) shows the timing t1 at which the control device 100 transmits frame A. Figure (2) shows that the control device 101 transmits frame B at a timing t2' earlier than the planned transmission timing t2. Therefore, since frames A and B are input to the network switch 103 via control network 1 and control network 2 with some overlap, the timing of each frame output from the network switch 103 to control network 3 is such that frames A and B are output with their intervals reduced, as shown in Figure (3). Consequently, it becomes possible to transmit frames without gaps in the frame intervals caused by delays in transmission timing due to time synchronization errors in the control device 101 or propagation delays in the network path.

[0059] Furthermore, Figure (4) shows that the control device 102 transmits frame C at a timing t3' earlier than the transmission timing t3. Therefore, frame C is input to the network switch 104 via control networks 3 and 4, partially overlapping with frame B which follows frame A. As a result, at the timing of each frame output from the network switch 104 to the control network 5, frames A, B, and C are output with their intervals shortened, as shown in Figure (5). Consequently, it becomes possible to transmit frames without gaps in frame intervals caused by delays in transmission timing due to time synchronization errors in the control device 102 or propagation delays in the network path.

[0060] Next, with reference to Figure 6, the range for determining the transmission timing of the control device will be explained. Figure 6 shows an example of the range for determining the transmission timing of the control device, and indicates the range for determining the transmission timing of frame B relative to frame A.

[0061] The transmission timing of frame B is set to be after the transmission timing of frame A, and furthermore, before the time synchronization error △ts. As a result, when frame A and frame B are input to the network switch, frame B will not overtake frame A, but will be output consecutively to frame A with a small gap between them. The time synchronization error △ts is the time synchronization error with the clock master by the aforementioned time synchronization unit 402, and is a value detected during the time synchronization operation. The network switch is equipped with a buffer for transferring input frames, but only two frames will exist in that buffer, so the buffer will not overflow and the gap between transmitted frames can be minimized.

[0062] In this way, the transmission timing calculation unit 305 of the control device 100 calculates the frame transmission timing for each control device, and the control device 100 distributes the transmission timing. Each control device then transmits each frame according to the distributed transmission timing, so that there are no gaps between frames and the transmission bandwidth can be used effectively.

[0063] When multiple control devices are installed, the transmission timing can be calculated using network information and calculation conditions, for example, by an optimization problem solving process. Network information includes the network topology, the time synchronization error between each control device and the time master, the propagation delay time between each control device, the transfer period, and the transfer order. The calculation conditions are to set the frame transmission time to be after the transmission start time of the previous frame and before the transmission end time of the previous frame by the time synchronization error, so as to partially overlap with the previous frame. Alternatively, one can find the optimal value by actually sending and receiving test frames while changing the transmission timing. Furthermore, the transmission timing may be calculated before the control system is operational, or when the network topology is changed.

[0064] Figure 7 shows the transmission timing information 70 for each control device obtained by the transmission timing calculation unit 305. The transmission timing information 70 is distributed to each control device by the distribution unit 306. One possible method of distribution is to store it in the user-defined area of ​​the time synchronization packet in the time synchronization protocol.

[0065] Furthermore, although the above explanation shows an example where the control device 100 is equipped with a function to calculate the transmission timing, a dedicated device connected to the control network, or a monitoring device or control terminal that manages the entire control system, may also be equipped with a function to calculate the transmission timing. The basic configuration of these devices is the same as that of the control device 100.

[0066] Next, an example of the control device's operating timing will be explained with reference to Figure 8. Figure 8 is a timing chart showing an example of the operating timing of control device 100, control device 101, and control device 102, illustrating the state in which the control system executes processing based on a predetermined shared period.

[0067] The part indicated by the symbol a in Figure 8 shows that the shared data of control device 100, control device 101, and control device 102 are shared during the control cycle.

[0068] Control device 100 shares data, and when the data sharing time for control device 100 ends, control device 101 shares the data, and when the data sharing time for control device 101 ends, control device 102 shares the data. Then, when the data sharing time for control device 102 ends, the CPU of each control device performs other processing such as calculations and control until the start time of the next control cycle. Here, as mentioned above, by adjusting the transmission timing of frames for each control device, the interval between each frame is shortened during transmission, so that data can be reliably shared within the sharing cycle without delay. Each control device acquires and holds quality information such as sensor information and time synchronization information until the next data sharing time, and each control device updates the shared data with each sharing cycle.

[0069] In other words, during the data sharing period, each control unit performs the necessary sensing and time synchronization processing. Then, when the data sharing period for control unit 102 ends, the CPU of each control unit performs other processing such as calculations and control until the start time of the next sharing cycle.

[0070] The part indicated by the symbol b in Figure 8 shows that the control device 102 calculates the control command and shares the calculation result (control command).

[0071] When the data sharing time for control device 101 ends, control device 102 calculates a control command based on the sensor information, which is shared data transmitted from control devices 100 and 101, and the sensor information in control device 102.

[0072] Then, during the next data sharing time, the obtained calculation results (control commands) are shared (i.e., the control device 102 transmits the obtained calculation results (control commands) to the control devices 100 and 101), and the control devices 100 and 101 execute control on the corresponding motors and actuators based on the control commands transmitted from the control device 102. At that time, for example, the control command unit (not shown) of the control device 100 adjusts the control command value based on the shared quality information, and the control command value is shared again as shared data.

[0073] As described above, according to the first embodiment, it becomes possible to transmit information and control commands from each sensor without gaps in the frame, thus enabling reliable data sharing within the sharing cycle without delay.

[0074] <Second Embodiment> Next, the configuration of the control system according to the second embodiment will be described with reference to Figures 9-10. Figure 9 is a diagram showing an example of the configuration of the control system according to the second embodiment.

[0075] In the second embodiment, the control system consists of control devices (control A) 100, (control B) 101, (control C) 102, (control D) 105, and 500, which are connected via network switches 103, 104, and 107 to form a distributed control system. In this embodiment, control device 500 has a function to calculate and distribute the transmission timing of frames from other control devices, and the calculated transmission timing information is distributed to each control device.

[0076] Figure 10 is a timing chart showing an example of the operating timing of the control device according to the second embodiment, illustrating the state in which the control system performs processing based on a predetermined shared period.

[0077] Figure (1) shows the frame transmission timing of the control devices (100, 101, 102) calculated by the control device 500. Figure (2) shows the output timing of frame A of the control device 100, and Figure (3) shows the output timing of frame A to the control network 2 by the network switch 103, with a delay due to the processing time (tds3) of the network switch 103. Furthermore, Figure (4) shows the arrival timing of frame A to the network switch 107, with a delay due to the propagation delay time (tdt2) of the control network 2.

[0078] Similarly, Figure (5) shows the output timing of frame B from the control device 101, and Figure (6) shows the output timing of frame B from the network switch 104 to the control network 4, with a delay due to the processing time (tds4) of the network switch 104. Figure (7) shows the arrival timing of frame B to the network switch 107, with a delay due to the propagation delay time (tdt4) of the control network 4.

[0079] Figure (8) shows the output timing of frame C from the control device 102, and Figure (9) shows the output timing of frame C to the control network 4 from the network switch 107, with a delay due to the processing time (tds7) of the network switch 107. Figure (10) shows the arrival timing of frame C to the network switch 104, with a delay due to the propagation delay time (tds4) of the control network 4.

[0080] Here, Figure (11) shows the arrival timing of frames A and B to control device 102, showing that frames A and B arrive without any gaps. Similarly, Figure (12) shows the arrival timing of frames B and C to control device 100, showing that frames B and C arrive without any gaps. Figure (13) shows the arrival timing of frames A and C to control device 101, showing that frames A and C arrive without any gaps. Furthermore, Figure (14) shows the arrival timing of frames A, B, and C to control device 105, showing that frames A, B, and C arrive without any gaps. In this way, by partially overlapping the frame transmission time with the immediately preceding transmission frame, the gap between each frame arriving at each control device is minimized, enabling reliable data sharing within the sharing period without delay.

[0081] <Third Embodiment> Next, an embodiment in which the control device described above is applied to a steelmaking system will be described. Figure 11 is an explanatory diagram illustrating an example in which the control device described in the second embodiment is applied to a steelmaking system.

[0082] In the steel system, the steel hot rolling equipment 800 is controlled by control devices 100, 101, 102, 105, and 106. Control devices 100, 101, 102, 105, and 106 are connected to a control network (1, 2, 3, 4, 5, 6, 7) via network switches (103, 104) and controlled by a control terminal 500. Here, the control terminal 500 (first control device) has the function of calculating the frame transmission timing of each control device and distributes the calculated frame transmission timing information to each control device. Furthermore, the connected control devices 100, 101, 102, 105, and 106, and the control terminal are synchronized in time, for example, with control device 105 as the clock master.

[0083] The steel heated in the heating furnace 801 is fed into the hot rolling equipment 800. The hot rolling equipment 800 includes a roughing mill 802, a finishing mill 803, a cooling equipment 804, and a winding machine 805.

[0084] The temperature of the heating furnace 801, acquired by the temperature sensor 700, is input to the control device 100 via the field network 601.

[0085] The control device 101 controls the feed control / plate speed sensor unit 701 to adjust the rotational speed of the roughing mill 802 and detect the feed rate of the steel.

[0086] The control device 102 controls the rolling control and plate thickness sensor unit 702, adjusting the rotation speed and tension of the finishing rolling mill 803 to detect the steel plate thickness.

[0087] The temperature of the cooling equipment 804, obtained by the temperature sensor 703, is input to the control device 105.

[0088] The control device 106 controls the winding control, plate thickness sensor, and plate speed sensor unit 704, adjusts the rotational speed of the winding machine 805, and detects the steel plate thickness and steel winding speed. The control device 106 also performs calculations for control commands to each control device.

[0089] According to this embodiment, each control device can transmit information and control commands from each sensor without gaps in the frame, enabling reliable data sharing within the shared cycle without delay, and providing a control system for manufacturing steel that maintains high accuracy stably.

[0090] <Fourth Embodiment> Next, an embodiment in which the control device described above is applied to a Factory Automation (FA) control system will be described. Figure 12 is an explanatory diagram illustrating an example in which the control device described in the second embodiment is applied to an FA system.

[0091] The monitoring terminal 521 and the control devices (120, 121, 122) are connected via network switches 103 and 104 through the control network (1, 2, 3, 4, 5). This allows the monitoring terminal to control the control devices (120, 121, 122). The control devices (121, 122, 123) are synchronized with control device 120 as the clock master. Here, the monitoring terminal 521 (first control device) has the function of calculating the frame transmission timing for each control device and distributes the calculated frame transmission timing information to each control device.

[0092] Control device 120 controls the connected PLCs (Programmable Logic Controllers) 720 and PLC 721, and control device 121 controls the connected PLC 722. Control device 122 also controls PLC 723. These are connected via a field network (621, 622, 623).

[0093] PLC720 controls the picking robot 822, PLC721 controls the conveyor motor 823 and camera 821, PLC722 controls the painting robot 824, and PLC723 controls the camera 825.

[0094] Products (objects to be manufactured) placed on the belt conveyor 826 are positioned in a predetermined location and orientation (for example, the correct orientation of the product) by a picking robot 822 controlled by a PLC 720. The belt conveyor 826 moves at a predetermined speed by a conveyor motor 823 controlled by a PLC 721. Products moving on the belt conveyor 826 are photographed by a camera 821 controlled by a PLC 721, and this camera 821 observes whether the product is placed in the predetermined location.

[0095] PLC721 acquires images of the product captured by camera 821 and performs an inspection to determine whether the product is placed in the designated position. Painting robot 824, controlled by PLC722, paints the surface of the product. Camera 825, controlled by PLC723, photographs the painted product and observes whether the product is painted correctly. PLC723 acquires images of the product captured by camera 825 and performs an inspection to determine whether the product is painted correctly.

[0096] Then, camera information (sensor information) from camera 821 is input to control device 120, and camera information (sensor information) from camera 852 is input to control device 122.

[0097] Furthermore, control devices 120 and 122 share the incoming camera information, and control device 120 calculates control commands for the picking robot 822 based on the shared data. Control device 122 also calculates control commands for the painting robot 824 based on the shared data.

[0098] The picking robot 822 places the products, the camera 821 photographs the products, and the painting robot 824 paints the products. The time when the camera 825 photographs the products is managed by the time synchronization unit 402 of the control device.

[0099] According to this embodiment, each control device can transmit information and control commands from each sensor without gaps in the frame, enabling reliable data sharing within the shared cycle without delay, and providing a control system that can manufacture products with stable and high accuracy.

[0100] Furthermore, the control device described in the first embodiment can be used in a variety of control systems, including FA systems and steelmaking systems, as well as water and wastewater treatment systems, power generation control systems, elevator control systems, railway control systems, automobile control systems, and construction machinery control systems.

[0101] The present invention is not limited to the embodiments described above, but includes various modifications and equivalent configurations within the spirit of the attached claims. For example, the embodiments described above are described in detail for the purpose of clearly illustrating the present invention, and the present invention is not necessarily limited to having all the configurations described. Furthermore, some of the configurations of one embodiment may be replaced with those of another embodiment. Furthermore, configurations of other embodiments may be added to the configuration of one embodiment. Furthermore, some of the configurations of each embodiment may be added, deleted, or replaced with those of other embodiments.

[0102] Furthermore, each of the aforementioned configurations, functions, processing units, and processing means may be implemented in hardware, for example, by designing them as integrated circuits, or they may be implemented in software by having a processor interpret and execute programs that realize each function.

[0103] Information such as programs, tables, and files that implement each function can be stored in memory, hard disks, SSDs (Solid State Drives), or other storage media such as IC cards, SD cards, and DVDs.

[0104] Furthermore, the control lines and information lines shown are those deemed necessary for explanation purposes and do not necessarily represent all control lines and information lines required for implementation. In reality, it can be assumed that almost all components are interconnected. [Explanation of symbols]

[0105] 1, 2, 3, 4, 5, 6, 7, 8…Control network, 20, 21, 22, 601, 621…Field network, 10, 13, 15, 16…Sensors, 11, 14…Motors, 12…Actuators, 100, 101, 102, 105, 106, 120, 121, 122…Control devices, 103, 104, 107…Network switches, 1001, 1011, 1021…CPU, 1002, 1012, 1022…Memory, 1003…Communication control unit, 1004…Interface unit, 1005…Non-volatile storage medium, 1006…Bus, 1007…Input / output unit, 301, 401…Communication unit, 302…Information collection unit, 303…Information storage unit, 304…Calculation condition setting unit, 305…Transmission timing calculation Output unit, 306…Distribution unit, 402…Time synchronization unit, 403…Frame buffer, 404…Transmission timing information acquisition unit, 405…Transmission timing adjustment unit, 406…Transmission data generation unit, 500…Control terminal, 521…Monitoring terminal, 700, 703…Temperature sensor, 701…Feed control / plate speed sensor, 702…Rolling control / plate thickness sensor, 704…Winding control / plate thickness sensor / plate speed sensor, 720, 721, 722, 723…PLC, 800…Rolling equipment, 801…Heating furnace, 802…Roughing mill, 803…Finishing mill, 804…Cooling equipment, 805…Winding machine, 822…Picking robot, 821…Camera, 823…Conveyor motor, 824…Painting robot, 825…Camera, 826…Belt conveyor.

Claims

1. A control device included in a control system that performs control on a controlled object using a time-synchronized control device, A communication unit that transmits and receives information regarding the control device included in the control system, An information collection unit collects network connection information of the control system via the aforementioned communication unit, The information storage unit for storing the aforementioned network connection information, A calculation condition storage unit stores calculation conditions used to calculate the frame transmission time, which relates to the time when the control device transmits a frame. A transmission time calculation unit calculates the frame transmission time based on the collected network connection information and the calculation conditions, A distribution unit that distributes the frame transmission time, A control device characterized by comprising:

2. A control device according to claim 1, The network connection information includes any of the following: network topology, time synchronization error with the time master, propagation delay time between each control device, transfer period, or transfer order. A control device characterized by the following features.

3. A control device according to claim 1, The calculation condition is that the frame transmission time is calculated to partially overlap with the immediately preceding transmission frame. A control device characterized by the following features.

4. A control device according to claim 3, The calculation condition is that the frame transmission time is calculated to be later than the transmission start time of the immediately preceding frame, and earlier than the transmission end time of the immediately preceding frame by the amount of the time synchronization error. A control device characterized by the following features.

5. A control device according to claim 1, The transmission time calculation unit, The frame transmission time is calculated by processing an optimization problem. A control device characterized by the following features.

6. A control device according to claim 1, The transmission time calculation unit, Before the control system is activated, the frame transmission time is calculated. A control device characterized by the following features.

7. A control device according to claim 1, The transmission time calculation unit, When the network topology is changed, the frame transmission time is calculated. A control device characterized by the following features.

8. A control system that synchronizes the time of a control device and performs control on a controlled device, The control system is It comprises a first control device and a second control device, The first control device is A communication unit that transmits and receives information regarding the control device included in the control system, An information collection unit collects network connection information of the control system via the aforementioned communication unit, The information storage unit for storing the aforementioned network connection information, A calculation condition storage unit stores calculation conditions used to calculate the frame transmission time, which relates to the time when the control device transmits a frame. A transmission time calculation unit calculates the frame transmission time based on the collected network connection information and the calculation conditions, The system includes a distribution unit that distributes the frame transmission time, The second control device is The control system includes a communication unit that transmits and receives information regarding the control device included in the control system, The communication unit receives the frame transmission time distributed from the first control device and transmits a frame according to the frame transmission time. A control system characterized by the following:

9. A control system according to claim 8, The network connection information includes any of the following: network topology, time synchronization error with the time master, propagation delay time between each control device, transfer period, or transfer order. A control system characterized by the following:

10. A control system according to claim 8, The calculation condition is that the frame transmission time is calculated to partially overlap with the immediately preceding transmission frame. A control system characterized by the following:

11. A control system according to claim 10, The calculation condition is that the frame transmission time is calculated to be later than the transmission start time of the immediately preceding frame, and earlier than the transmission end time of the immediately preceding frame by the amount of the time synchronization error. A control system characterized by the following:

12. A control system according to claim 8, The transmission time calculation unit of the first control device is: The frame transmission time is calculated by processing an optimization problem. A control system characterized by the following:

13. A control system according to claim 8, The transmission time calculation unit of the first control device is: Before the control system is activated, calculate the frame transmission time. A control system characterized by the following:

14. A control system according to claim 8, The transmission time calculation unit of the first control device is: When the network topology is changed, the frame transmission time is calculated. A control system characterized by the following:

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