JP2024067281A - Control device and control system - Google Patents

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

The present invention relates to a control device and a control system.

Control systems are installed in various social infrastructure systems. Social infrastructure systems are automated and made more efficient by automating and streamlining the control systems using multiple control devices that perform calculations.

The control device that constitutes this type of control system acquires information such as various state quantities from detection devices such as sensors installed in the field, and the central processing unit of the control device executes calculation processing. The control device then outputs control commands to operating devices such as motors and actuators installed in the field, and controls the operating devices to be controlled in real time.

For example, in a control system for a large-scale social infrastructure system, multiple control devices are connected via a common network to form a distributed control system. The distributed control system performs calculation processing based on information acquired from multiple detection devices installed in a vast field. As an example, such a distributed control system is thought to perform highly efficient control by dividing the roles of a control device that executes calculation processing and a control device that outputs control commands.

The shared memory method is one method for synchronizing data between control devices in a distributed control system. In the shared memory method, each control device that makes up the distributed control system has a shared memory in the memory implemented in each control device, and each control device transmits data stored in the shared memory to the other control devices. This allows data to be shared between the control devices, reducing the communication load between the control devices. In this case, the control devices synchronize their time with each other, transmit the data stored in the shared memory at the same time, and output control commands for the controlled object, which allows for high-precision real-time control, such as simultaneous processing of multiple processes or processing at a desired time in a chronological order. For this reason, information for time synchronization is exchanged and each control device synchronizes its time.

As background technology in this technical field, for example, there is JP 2019-41264 A (Patent Document 1). Patent Document 1 describes a communication system in a wireless multi-hop network that compares the number of hops between a base station and an adjacent node and adjusts the transmission timing of a time slot assigned to the station.

JP 2019-41264 A

In the communication system described in Patent Document 1, the number of hops from the base station of the own node and adjacent nodes is compared, and transmission timing is adjusted using available slots allocated to adjacent nodes to avoid collisions with time slots allocated to previous and subsequent nodes. However, Patent Document 1 does not appear to describe any technology for making effective use of the transmission band. Therefore, there are thought to be problems in making effective use of the transmission band.

A representative example of the invention disclosed in the present application is as follows. That is, the control device is included in a control system that executes control over a controlled device using a control device with time synchronization. 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 the calculation conditions used to calculate a frame transmission time related 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 the calculation conditions. The distribution unit distributes the frame transmission time. Another example is as follows. That is, the control device is included in a control system that executes control over a controlled device using a control device with time synchronization. The communication unit transmits and receives information about the control device included in the control system. The communication unit receives a frame transmission time related to the time when the distributed frame is to be transmitted, and transmits the frame according to the frame transmission time.

A representative example of the invention disclosed in the present application is as follows. That is, a control system synchronizes the time of a control device and executes control over a controlled device. The control system includes a first control device and a second control device. The first control device includes 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 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 the calculation conditions used to calculate the frame transmission time related 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 the calculation conditions. The distribution unit distributes the frame transmission time. The second control device includes a communication unit. In this second control device, the communication unit receives the frame transmission time distributed from the first control device and transmits the frame according to the frame transmission time.

According to one aspect of the present invention, by distributing an appropriate frame transmission time, it is possible to realize effective use of the transmission bandwidth in the control system. Problems, configurations, and effects other than those described above will become clear from the description of the following embodiment.

FIG. 1 is a diagram illustrating an example of the configuration of a control system according to a first embodiment. FIG. 2 is an explanatory diagram illustrating an example of the configuration of a control device. FIG. 2 is a diagram illustrating an example of a functional configuration of a control device. FIG. 13 is a diagram illustrating an example of another functional configuration of the control device. 10 is a timing chart showing an example of frame transmission timing of a control device. FIG. 13 is a diagram illustrating an example of a range in which a control device determines a transmission timing. FIG. 11 is a diagram showing an example of the contents of transmission timing information of the control device. 4 is a timing chart showing an example of operation timing of the control device. FIG. 11 is a diagram illustrating an example of the configuration of a control system according to a second embodiment. 10 is a timing chart showing an example of frame transmission timing of a control device. FIG. 13 is an explanatory diagram illustrating an example in which the control device is applied to a steelmaking system according to a third embodiment. FIG. 13 is an explanatory diagram illustrating an example in which the control device is applied to an FA system according to a fourth embodiment.

Embodiments of the present invention will be described below with reference to the drawings. Note that substantially the same or similar configurations are given the same reference numerals, and where explanations are repeated, they may be omitted.

In the embodiment, a control device is described that solves the problem of realizing effective use of the transmission bandwidth by calculating the transmission timing based on network connection information so as to minimize the gap between transmission frames. By using this control device, the transmission bandwidth is effectively used, and as a result, highly accurate control is performed well, making a contribution from an economic perspective.

First Embodiment
First, a control system according to a first embodiment will be described with reference to Figures 1 to 8. Figure 1 is a diagram showing the configuration of the control system according to the first embodiment.

As shown in FIG. 1, the control system of the first embodiment is configured by connecting a control device (control A) 100, a control device (control B) 101, and a control device (control C) 102 to a control network (1, 2, 3, 4) via a network switch 103 and a network switch 104, forming a distributed control system. In addition, a control network 5 is connected to other control devices, etc., not shown.

The control devices (100, 101, 102) output control commands (control data such as control signals and command values) to operation devices (controlled devices that are the objects to be controlled) such as motor A11, motor B14, and actuator A12 installed in the field, and control the operation devices in real time. In other words, the distributed control system is composed of control devices that execute control over the operation devices.

The control networks (1 to 5) to which the devices are connected are networks that improve the time determinism of communication delays between control devices by using time-slot communication based on time-division control, such as networks that perform data communication using a communication method configured according to the IEEE standard called TSN (Time Sensitive Network) or industrial networks standardized by IEC 61784. The connection form may also be a wired connection or a wireless connection such as a mobile phone network or wireless LAN.

Sensor A10, motor A11, and actuator A12 are connected to control device 100 via field network 20. Similarly, sensor B13 and motor B14 are connected to control device 101 via field network 21, and sensor C15 and sensor C16 are connected to control device 102 via field network 22.

The field network (20, 21, 22) may be, for example, a network defined by IEC 61158. Digital signals and analog signals may be input and output by directly connecting the control device 100, etc. to the sensor A10, etc. or the actuator A12, etc. In this case, the control device 100, etc. and the sensor A10, the actuator A12, etc. are connected by multiple input and output signal lines.

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

In this example, in particular, 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 the control commands with the control devices 100 and 101. On the other hand, the control device 100 controls the motor A11 and actuator A12 using the shared control commands, and similarly, the control device 101 controls the motor B14 using the shared control commands.

Sensors A10, B13, C15, and C16 installed in the field are detection devices that detect and acquire information, which is state quantities such as various flow rates, temperatures, pressures, tensions, and rotational speeds.

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.

The control device 100 has 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.

Note that while the control device 100 will be described here, the basic configuration of the control devices 101 and 102 is the same as that of the control device 100.

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

The memory 1002 has a temporary storage area that is used when the CPU 1001 is operating, and stores, for example, an operating system (hereinafter referred to as OS) and application programs transferred from the non-volatile storage medium 1005.

In addition, memory 1002 is provided with an area for storing program A running on each control device, an area for storing retained information A acquired by each control device (information acquired by each control device from a detection device or a controlled object), and an area for storing shared data (acquired information and control commands acquired by control A) shared between each control device via control network 1.

The communication control unit 1003 executes data communication with the control devices 101 and 102 via the control network 1. For example, the function of the MAC (Media Access Control) layer of the IEEE 802.3 standard may be implemented as the data communication method. In accordance with this standard, a frame is generated in which destination information, error correction code, etc. are added to the transmitted and received data. Examples of the implementation of the communication control unit 1003 include an IC (Integrated Circuit), an FPGA (Field Programmable Gate Array), and a gate array. The communication control unit 1003 may also be configured as an integrated unit with the CPU 1001.

Furthermore, the communication control unit 1003 has a function of exchanging time synchronization packets using a network to execute a time synchronization protocol. In other words, the communication control unit 1003 has a clocking function when transmitting and receiving time synchronization packets, and a function of setting and adding correction values to time synchronization packets. IEEE1588, IEEE802.1AS, NTP, and SNTP are used as such time synchronization protocols. The communication control unit 1003 also has a time management function based on the synchronized time, and communicates synchronized time information to the control devices 101 and 102.

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 function of IEEE 802.3. The interface unit 1004 may be included in the communication control unit 1003.

In FIG. 2, the control device 100 has one communication control unit 1003 and one interface unit 1004, but may have multiple communication control units 1003 and multiple interface units 1004.

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.

The non-volatile storage medium 1005 is, for example, a hard disk drive, a solid state drive, a flash memory, or the like. The non-volatile storage medium 1005 may also be an easily removable external storage medium such as a USB memory or a solid state drive.

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

The bus 1006 connects the CPU 1001, the memory 1002, the communication control unit 1003, the non-volatile storage medium 1005, and the input/output unit 1007 so that they can communicate with each other.

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

The control device shown in FIG. 3 (which is a control device that determines a frame transmission time related to the time when the control device transmits a frame, and which may be referred to as a first control device) has 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 has 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.

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 is composed of software that runs 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 device to other control devices via the control network 1, and receives information related to the other control devices from the other control devices. The communication unit 301 also transmits information acquired by its own control device regarding its own control device, and receives information acquired by the other control devices regarding the other control devices.

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

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

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

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.

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

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

The control device shown in FIG. 4 (which is a control device that transmits frames according to the distributed frame transmission time, and may be referred to as the second control device) has 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 FIG. 3 described above.

The time synchronization unit 402 executes a time synchronization procedure. The time synchronization protocols executed by the time synchronization unit 402 include the aforementioned IEEE 1588, IEEE 802.1AS, NTP, and SNTP. The time synchronization unit 402 uses the time measured by the communication unit 401 when a time synchronization packet is sent or received, and performs time synchronization with the control device 100 and the control device 102. In other words, the time synchronization unit 402 performs time synchronization with a clock master that serves as the time reference for the other control devices that make up the distributed control system. One control device is selected as the clock master from among the connected control devices according to a predetermined procedure.

The time synchronization unit 402 may be realized by an application running on the CPU 1001, and the communication control unit 1003 may be realized by a hardware logic circuit using an IC or FPGA. The time synchronization unit 402 may also be configured with both the software of the CPU 1001 and the hardware of the communication control unit 1003. In this case, the measurement function of the transmission timing and reception timing of the time synchronization packet and the generation of the time synchronization packet format may be processed by the communication control unit 1003.

The frame buffer 403 stores frames sent to and received from the communication unit 401 via the control network 2.

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

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.

The transmission data generation unit 406 generates data to be transmitted to other control devices and stores the data in the frame buffer 403. The transmission data generation unit 406 generates data including, for example, sensing data of other control devices and the acquired sensing data of the control device itself.

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 at the transmission timing specified by the communication unit 401.

Next, the operation timing of the control device according to the first embodiment will be described. FIG. 5 is a timing chart showing an example of the operation timing of the control device according to the first embodiment, and shows a state in which the control system executes processing based on a predetermined sharing period.

The portion indicated by the symbol a in FIG. 5 indicates the transmission time assigned in advance within the sharing period for the frames that transmit the shared data of the control devices 100, 101, and 102.

It is planned that control device 100 transmits frame A at time t1, and when the data sharing time of control device 100 ends, control device 101 transmits frame B at time t2, and when the data sharing time of control device 101 ends, control device 102 transmits frame C at time t3. These frames are set as close together as possible to make effective use of the transmission band (i.e., the range indicated by the symbol TB in FIG. 5).

The portion indicated by the symbol b in FIG. 5 indicates the transmission timing of each control device according to this embodiment. FIG. 5 (1) shows the timing t1 at which the control device 100 transmits frame A. FIG. 5 (2) shows that the control device 101 transmits frame B at timing t2', which is earlier than the planned transmission timing t2. Therefore, frames A and B are input to the network switch 103 via the control networks 1 and 2 so that they overlap partially, and the timing of each frame output from the network switch 103 to the control network 3 is such that frames A and B are output with the interval between them narrowed, as shown in FIG. 5 (3). Therefore, there is no gap between frames due to delays in the transmission timing caused by misalignment of the time of the control device 101 or propagation delays in the network path, and it becomes possible to transmit frames.

Furthermore, FIG. 4 (4) shows that the control device 102 transmits frame C at timing t3', which is earlier than transmission timing t3. Therefore, frame C is input to the network switch 104 via control networks 3 and 4 so that it overlaps partially with frame B, which follows frame A, so that 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 narrowed, as shown in FIG. 4 (5). Therefore, similarly, there is no gap between frames due to delays in the transmission timing caused by misalignment of the time of the control device 102 or propagation delays in the network path, and it becomes possible to transmit frames.

Next, the range of determination of the transmission timing of the control device will be described with reference to FIG. 6. FIG. 6 shows an example of the range of determination of the transmission timing of the control device, and shows the range of determination of the transmission timing of frame B relative to frame A.

The transmission timing of frame B is set to be later than the transmission timing of frame A, and further to be earlier than the time synchronization error Δts. As a result, when frames A and B are input to the network switch, frame B will not overtake frame A, but will be output in tandem with frame A with a narrower interval. The time synchronization error Δts is the error in time synchronization 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 since only two frames will exist in the buffer, the buffer will not overflow and it is possible to minimize the gaps between transmitted frames.

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.

When multiple control devices are installed, the transmission timing can be calculated from the network information and calculation conditions, for example, by optimization problem solving processing. The network information includes the network topology, the time synchronization error of each control device with the time master, the propagation delay time between each control device, the transfer period, and the transfer order, and the calculation conditions include setting the frame transmission time to be later than the transmission start time of the previous frame and earlier than the transmission end time of the previous frame by the time synchronization error, so that there is some overlap with the previous frame. Another method is to actually send and receive test frames while changing the transmission timing to find the optimal value. The transmission timing may be calculated before the control system is operated, or when the network topology is changed.

Figure 7 shows the transmission timing information 70 of each control device obtained by the transmission timing calculation unit 305, and the transmission timing information 70 is distributed to each control device by the distribution unit 306. One possible method of distribution is to store the information in a user-defined area of a time synchronization packet in the time synchronization protocol.

In the above explanation, an example was shown in which the control device 100 is provided with a transmission timing calculation function, but the transmission timing calculation function may also be provided in a dedicated device connected to the control network, or in a monitoring device or control terminal that manages the entire control system. The basic configuration of these is the same as that of the control device 100.

Next, an example of the operation timing of the control device will be described with reference to FIG. 8. FIG. 8 is a timing chart showing an example of the operation timing of the control device 100, the control device 101, and the control device 102, and shows a state in which the control system executes processing based on a predetermined shared period.

The portion indicated by the symbol a in FIG. 8 indicates that the shared data of the control device 100, the control device 101, and the control device 102 are shared during the control period.

The control device 100 shares data, and when the data sharing time of the control device 100 ends, the control device 101 shares data, and when the data sharing time of the control device 101 ends, the control device 102 shares data. Then, when the data sharing time of the control device 102 ends, the CPU of each control device executes another process such as calculation or control until the start time of the next control cycle. Here, as described above, the frame transmission timing of each control device is adjusted, so that the intervals between each frame are shortened and data can be shared reliably 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 shares the shared data while updating it every sharing cycle.

In other words, during the data sharing period, each control device performs the necessary sensing and time synchronization processing. Then, when the data sharing period of the 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 sharing period.

The part indicated by the symbol b in FIG. 8 indicates that the control device 102 calculates the control command and shares the calculation result (control command).

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

Then, at 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 of the corresponding motors and actuators based on the control commands transmitted from the control device 102. At that time, for example, a 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.

As described above, according to the first embodiment, it is possible to transmit information and control commands from each sensor without gaps between frames, so data can be shared reliably within the sharing period without delay.

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

In the control system of the second embodiment, control device (control A) 100, control device (control B) 101, control device (control C) 102, control device (control D) 105, and control device 500 are connected to a control network (1, 2, 3, 4, 5, 6, 7, 8) via network switch 103, network switch 104, and network switch 107 to form a distributed control system. In this embodiment, control device 500 has a function of calculating and distributing the transmission timing of frames from other control devices, and the calculated transmission timing information is distributed to each control device.

Figure 10 is a timing chart showing an example of the operation timing of the control device according to the second embodiment, showing the state in which the control system executes processing based on a predetermined sharing period.

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

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

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

Here, FIG. 11 shows the timing of frames A and B arriving at the control device 102, with no gaps between frames A and B. FIG. 12 shows the timing of frames B and C arriving at the control device 100, with no gaps between frames B and C. FIG. 13 shows the timing of frames A and C arriving at the control device 101, with no gaps between frames A and C. FIG. 14 shows the timing of frames A, B, and C arriving at the control device 105, with no gaps between frames A, B, and C. In this way, by overlapping the frame transmission time with the immediately preceding transmission frame, the gaps between the frames arriving at each control device are minimized, and data can be reliably shared within the sharing period without delay.

Third Embodiment
Next, an embodiment in which the above-mentioned control device is applied to an iron and steel system will be described. Fig. 11 is an explanatory diagram illustrating an example in which the control device described in the second embodiment is applied to an iron and steel system.

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

The steel heated in the heating furnace 801 is fed into the hot rolling equipment 800. The hot rolling equipment 800 has a roughing mill 802, a finishing mill 803, a cooling equipment 804, and a winder 805.

The temperature of the heating furnace 801 obtained by the temperature sensor 700 is input to the control device 100 via the field network 601.

The control device 101 controls the feed control/plate speed sensor unit 701, adjusts the rotation speed of the rough rolling mill 802, and detects the steel feed speed.

The control device 102 controls the rolling control/thickness sensor unit 702, adjusts the rotation speed and tension of the finishing rolling mill 803, and detects the thickness of the steel.

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

The control device 106 controls the winding control/thickness sensor/speed sensor unit 704, adjusts the rotation speed of the winder 805, and detects the thickness of the steel and the winding speed of the steel. The control device 106 also performs calculations of control commands for each control device.

According to this embodiment, each control device can transmit information and control commands from each sensor without gaps in the frame, so data can be shared reliably within the sharing period without delay, providing a control system for manufacturing steel with stable and high precision.

Fourth Embodiment
Next, an embodiment in which the above-mentioned control device is applied to an FA (Factory Automation) control system will be described. Fig. 12 is an explanatory diagram for explaining an example in which the control device described in the second embodiment is applied to an FA system.

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

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

Then, PLC 720 controls the picking robot 822, PLC 721 controls the conveyor motor 823 and the camera 821, PLC 722 controls the painting robot 824, and PLC 723 controls the camera 825.

Products (products) loaded onto the belt conveyor 826 are placed in a predetermined position and orientation (e.g., 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 along the belt conveyor 826 are photographed by a camera 821 controlled by the PLC 721, and this camera 821 observes whether or not the product has been placed in the predetermined position.

PLC721 acquires images of the product taken by camera 821 and performs an inspection to determine whether the product is installed in the specified position. A painting robot 824 controlled by PLC722 paints the surface of the product. A camera 825 controlled by PLC723 photographs the painted product and observes whether the product is painted correctly. PLC723 acquires images of the product taken by camera 825 and performs an inspection to determine whether the product is painted correctly.

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.

Furthermore, the control device 120 and the control device 122 share this input camera information, and the control device 120 calculates control commands for the picking robot 822 based on the shared data. Also, the control device 122 calculates control commands for the painting robot 824 based on the shared data.

The picking robot 822 places the product, the camera 821 photographs the product, and the painting robot 824 paints the product. The time at which the camera 825 photographs the product is managed by the time synchronization unit 402 of the control device.

According to this embodiment, each control device can transmit information and control commands from each sensor without gaps in the frames, so data can be shared reliably within the sharing period without delay, providing a control system that can manufacture products with stable and high precision.

The control device described in the first embodiment can be used in various control systems, such as FA systems, steelmaking systems, water and sewage treatment systems, power generation control systems, elevator control systems, railway control systems, automobile control systems, and construction machinery control systems.

The present invention is not limited to the above-described embodiments, and includes various modified examples and equivalent configurations within the spirit of the appended claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to having all of the configurations described. Furthermore, part of the configuration of one embodiment may be replaced with the configuration of another embodiment. Furthermore, the configuration of another embodiment may be added to the configuration of one embodiment. Furthermore, part of the configuration of each embodiment may be added, deleted, or replaced with other configurations.

Furthermore, each of the configurations, functions, processing units, processing means, etc. described above may be realized in part or in whole in hardware, for example by designing them as integrated circuits, or may be realized in software by a processor interpreting and executing a program that realizes each function.

Information such as programs, tables, and files that realize each function can be stored in a storage device such as a memory, hard disk, or SSD (Solid State Drive), or in a recording medium such as an IC card, SD card, or DVD.

In addition, the control lines and information lines shown are those considered necessary for explanation, and do not necessarily represent all control lines and information lines necessary for implementation. In reality, it is safe to assume that almost all components are interconnected.

1, 2, 3, 4, 5, 6, 7, 8...Control network, 20, 21, 22, 601, 621...Field network, 10, 13, 15, 16...Sensor, 11, 14...Motor, 12...Actuator, 100, 101, 102, 105, 106, 120, 121, 122...Control device, 103, 104, 107...Network switch, 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 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/strip speed sensor, 702...rolling control/strip thickness sensor, 704...winding control/strip thickness sensor/strip speed sensor, 720, 721, 722, 723...PLC, 800...rolling equipment, 801...heating furnace, 802...roughing mill, 803...finishing mill, 804...cooling equipment, 805...winder, 822...picking robot, 821...camera, 823...conveyor motor, 824...painting robot, 825...camera, 826...belt conveyor.

Claims (15)

A control device included in a control system that executes control of a controlled device using a time-synchronized control device,
A communication unit that transmits and receives information regarding a control device included in the control system;
an information collection unit that collects network connection information of the control system via the communication unit;
an information storage unit for storing the network connection information;
a calculation condition storage unit that stores a calculation condition used for calculating a frame transmission time related to a time when the control device transmits a frame;
a transmission time calculation unit that calculates the frame transmission time based on the collected network connection information and the calculation condition;
a distribution unit that distributes the frame transmission time;
A control device comprising: The control device according to claim 1 ,
The network information includes any one of a network topology, a time synchronization error with a time master, a propagation delay time between each control device, a transfer period, and a transfer order.
A control device comprising: The control device according to claim 1 ,
the calculation condition is a condition for calculating the frame transmission time so as to overlap a part of the immediately preceding transmission frame;
A control device comprising: The control device according to claim 3,
the calculation condition is a condition for calculating the frame transmission time to be later than a transmission start time of the immediately preceding frame and earlier than a transmission end time of the immediately preceding frame by a time synchronization error.
A control device comprising: The control device according to claim 1 ,
The transmission time calculation unit
Calculating the transmission time of the transmission frame by an optimization problem process;
A control device comprising: The control device according to claim 1 ,
The transmission time calculation unit
Calculating the transmission time of the transmission frame before the control system is operated.
A control device comprising: The control device according to claim 1 ,
The transmission time calculation unit
Calculating the transmission time of the transmission frame when the network topology is changed.
A control device comprising: A control device included in a control system that executes control of a controlled device using a time-synchronized control device,
A communication unit that transmits and receives information about a control device included in the control system,
the communication unit receives a frame transmission time related to a time to transmit the distributed frame, and transmits the frame in accordance with the frame transmission time.
A control device comprising: A control system that synchronizes the time of a control device and executes control over a controlled device,
The control system includes:
A first control device and a second control device are provided,
The first control device is
A communication unit that transmits and receives information regarding a control device included in the control system;
an information collection unit that collects network connection information of the control system via the communication unit;
an information storage unit for storing the network connection information;
a calculation condition storage unit that stores a calculation condition used for calculating a frame transmission time related to a time when the control device transmits a frame;
a transmission time calculation unit that calculates the frame transmission time based on the collected network connection information and the calculation condition;
a distribution unit that distributes the frame transmission time,
The second control device is
A communication unit that transmits and receives information about a control device included in the control system,
the communication unit receives the frame transmission time distributed from the first control device, and transmits the frame in accordance with the frame transmission time.
A control system comprising: 10. The control system of claim 9,
The network information includes any one of a network topology, a time synchronization error with a time master, a propagation delay time between each control device, a transfer period, and a transfer order.
A control system comprising: 10. The control system of claim 9,
the calculation condition is a condition for calculating the frame transmission time so as to overlap a part of the immediately preceding transmission frame;
A control system comprising: 12. The control system of claim 11,
the calculation condition is a condition for calculating the frame transmission time to be later than a transmission start time of the immediately preceding frame and earlier than a transmission end time of the immediately preceding frame by a time synchronization error.
A control system comprising: 10. The control system of claim 9,
The transmission time calculation unit of the first control device
Calculating the transmission time of the transmission frame by an optimization problem process;
1. A control system comprising: 10. The control system of claim 9,
The transmission time calculation unit of the first control device
Calculating the transmission time of the transmission frame before the control system is operated;
A control system comprising: 10. The control system of claim 9,
The transmission time calculation unit of the first control device
Calculating the transmission time of the transmission frame when the network topology is changed.
1. A control system comprising:

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