JP6409520B2 - Control system and relay device - Google Patents

Description

  The present invention relates to a relay device that mediates communication between a control device and a network in a control system.

In industrial facilities such as factories and various plants, a communication system called a control system is often constructed to control various operations. The control system includes a control device that collects monitoring data from sensors installed in an industrial facility and performs drive control of an electric motor or the like according to the collection result. Such control devices include DCS (Distributed).
Control System: a distributed control system or a distributed control device) or a programmable logic controller (hereinafter, PLC) is used. In a general FA (Factory Automation) system, PLC is often used as a control device, and in plant facilities that require high reliability, DCS is often used as a control device. This is because DCS is more reliable than PLC.

  The control system often includes a plurality of types of networks that mediate communication between the control device and other devices. Specific examples of the network included in the control system include an IO network and a control network. The IO network is connected to devices (such as the sensors described above) that are targets of collection of monitoring data by the control device and control target devices such as electric motors (hereinafter, both are collectively referred to as “IO devices”). On the other hand, one or a plurality of other control devices, an HCI device for system monitoring, and the like are connected to the control network. As a connection mode of these networks to the control device, there is a mode of directly connecting to the control device, but there is also a mode of connecting via a relay device (for example, a gateway device) such as a network device.

JP 2013-54584 A

  This type of network device is a relay device specialized for relaying data communication between a network and a control device. For this reason, this type of network device has a problem that data communication cannot be smoothly relayed between a plurality of networks, and it is necessary to share part or all of the data between the plurality of networks included in the control system. In some cases it was a problem. For example, as shown in FIG. 7, in a control system including a network 40A and a network 40B and connecting these networks to the control device 20 via the network device 10 ′, the monitoring data transmitted from the IO device 11 is transmitted to other When the control device (the control device 21 in the example shown in FIG. 7) is also referred to, the monitoring data is transferred from the network device 10 ′ → the control device 20 → the network device 10 ′ → the network 40B → the control device 21 to the transfer path C0. There is a problem that a transmission delay corresponding to the reciprocation between the network device 10 ′ and the control device 21 occurs.

  The present invention has been made in view of the above problems, and in a control system configured by connecting a plurality of networks and a control device by a network device, data between the plurality of networks while avoiding occurrence of transmission delay. The purpose is to provide a technology for realizing sharing.

  In order to solve the above-described problems, the present invention includes a control device and a relay device that is connected to the control device and a plurality of networks and transfers data transmitted from each network to the control device to the control device. The relay apparatus in the control system is provided with the following transfer determination reference table, determination means, and data transfer means. Information indicating whether or not a part or all of data transmitted from each of the plurality of networks to the control device needs to be transferred to another network is written in the transfer determination criterion table. . The determination means determines whether or not it is necessary to transfer a part or all of the received data to another network each time data transmitted from each of the plurality of networks to the control device is received. Judgment is made with reference to the reference table. The data transfer means includes a part or all of the data determined to be transferable by the determination means together with data transmitted from the control device to the transfer destination network of part or all of the data (for example, both of them) Merge) and transfer to the network.

  In the control system of the present invention, among the data transferred from each of the plurality of networks to the control device, the data that needs to transfer a part or all of the data to another network is the network device and the control device. It is transferred to the other network without going back and forth. Therefore, according to the present invention, transmission delay does not occur when data sharing between networks is realized. In addition, although patent document 1 describes the invention of the data relay apparatus in the cyclic transmission of the shared memory system, this data relay apparatus does not connect the control apparatus in the control system and a plurality of networks. This technique is completely different from the present invention.

Further, as another aspect of the present invention, an aspect in which the relay device is provided alone, a CPU (Central
It is conceivable to provide a program that causes a general computer such as a processing unit to function as the determination unit and the data transfer unit. According to the former aspect, by replacing the relay device in the existing control system with the relay device of the present invention, there is an effect that the existing control system can function as the control system of the present invention. Further, according to the latter aspect, the relay control program of the relay device in the existing control system is replaced with the above program so that the existing relay device functions as the relay device of the present invention, and the existing control system is This makes it possible to function as a control system.

  As described above, according to the present invention, in a control system configured by connecting a plurality of networks and a control device with a network device, data sharing between the plurality of networks is realized while avoiding transmission delay. It becomes possible to do.

It is a figure showing an example of composition of control system 1 of one embodiment of the present invention. 4 is a diagram illustrating an example of data flowing in a network 40A or a network 40B included in the control system 1. FIG. 4 is a diagram illustrating a transfer path of data transmitted from the network 40A and transferred to the network 40B in the control system 1. FIG. 2 is a diagram illustrating a configuration example of a network device 10 included in the control system 1. FIG. It is a figure which shows an example of the transfer determination reference | standard table 134b. It is a flowchart which shows each flow of the reception task and transmission task which the control part 110 of the network apparatus 10 performs. It is a figure which shows the flow of the data transmitted from one network in the conventional control system containing the network apparatus connected to two networks, and transferred to the other network.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(A: Configuration)
FIG. 1 is a diagram illustrating a configuration example of a control system 1 according to an embodiment of the present invention.
In FIG. 1, the same components as those in FIG. 7 are denoted by the same reference numerals. As apparent from the comparison between FIG. 1 and FIG. 7, the control system 1 includes a network device 10 instead of the network device 10 ′, a support tool 30 connected to the control device 20, and The control system shown in FIG. 7 is different in that the HCI device 23 is connected to the network 40B.

  The support tool 30 is a personal computer in which various software that realizes operation support of the control device 20 is installed. In the present embodiment, the support tool 30 generates system definition information that is referred to when the control device 20 and the network device 10 are operated, generates an application program to be executed by the control device 20, and these system definition information and application program. Is used for downloading to the control device 20. Such a support tool also exists in a conventional control system, and is simply omitted in FIG.

  The network 40A is an IO network, and the IO device 11 and the IO device 12 are connected to the network 40A. Each of the IO device 11 and the IO device 12 includes various sensors, and transmits output data of the sensors to the control device 20 as input data to the control device 20. Hereinafter, data transmitted from the IO device 11 or the IO device 12 to the control device 20 is referred to as “monitoring data”. The network device 10 transfers data transmitted from the network 40A to the control device 20. The control device 20 is, for example, a PLC, and controls the operation of a control target device (for example, an electric motor, not shown in FIG. 1) according to the received monitoring data.

  The network 40B is a control network. The control device 21, the control device 22, and the HCI device 23 are connected to the network 40B. The control device 21 and the control device 22 are PLCs like the control device 20. Each of the control device 21 and the control device 22 performs operation control of another control target device (not shown in FIG. 1) different from the control target device of the control device 20. The HCI device 23 is a personal computer having a liquid crystal display or the like, and is a device for causing the operation manager of the control system 1 to monitor the operation state of the control device 21, the control device 22, or the IO devices 11 and 12. Such an HCI device also exists in a conventional control system, but is merely omitted in FIG.

  Data transmitted from the network 40A to the control device 20 in the control system 1 must be transferred to the network 40B (also used by the control device 21 and the control device 22 or monitored by the HCI device 23). Stuff). For example, as shown in FIG. 2, among the monitoring data (input data 111 to 118) transmitted from the IO device 11 to the control device 20 with the IO network header added, the control network header is used for the input data 111 to 114. It must be given and transferred to the control device 21 as well. The IO network header is header information that complies with the communication protocol in the network 40A, and includes information indicating the type of data following the header information, a transmission source station, a transmission destination, and the like. Similarly, the control network header is header information conforming to the communication protocol in the network 40B, and includes information indicating the type of data, the transmission source station, the transmission destination, and the like following the header information. As shown in FIG. 2, in the control system 1, in addition to the input data 111 to 114, the input data 123 and 124 and the operation result data 021 to 024 are transferred to the control device 21, and the control device 21 stores these data. The operation control of the device to be controlled is performed with reference. The input data 123 and 124 are monitoring data transmitted from the IO device 12, and the calculation result data 021 to 024 are data generated by the control device 20.

  As described above, when the monitoring data transmitted from the network 40A includes data that needs to be transferred to the network 40B, the network 40A → the network device 10 → the control device 20 → the network device 10 in the conventional control system. → It is necessary to cause each of the network device 10 and the control device 20 to execute processing for transferring the corresponding data along the transfer path such as the network 40B. On the other hand, in the present embodiment, by causing the network device 10 to execute processing that clearly shows the characteristics of the present invention, the network device 10 → the control device 20 → the network device 10 does not go through an extra transfer path, The corresponding monitoring data can be transferred from the network 40A to the network 40B along the transfer path C1 shown in FIG. Hereinafter, the network device 10 that clearly shows the features of the present embodiment will be mainly described.

  FIG. 4 is a block diagram illustrating a configuration example of the network device 10. As shown in FIG. 4, the network device 10 includes a control unit 110, a first communication interface (hereinafter, “I / F”) unit 120a, a second communication I / F unit 120b, a third communication I / F unit 120c, A storage unit 130 and a bus 140 that mediates data exchange between these components are included.

  The control unit 110 is a CPU, for example. The control unit 110 functions as a control center of the network device 10 by executing the relay control program 134a stored in the storage unit 130 (more precisely, the nonvolatile storage unit 134). Details of processing executed by the control unit 110 in accordance with the relay control program 134a will be made clear later.

  Each of the first communication I / F unit 120a, the second communication I / F unit 120b, and the third communication I / F unit 120c is, for example, a NIC (Network Interface Card). The first communication I / F unit 120a is connected to the network 40A. The first communication I / F unit 120a delivers the data received from the network 40a to the control unit 110, and sends the data delivered from the control unit 110 to the network 40A. The second communication I / F unit 120b is connected to the network 40B. The second communication I / F unit 120b delivers the data received from the network 40B to the control unit 110, and sends the data delivered from the control unit 110 to the network 40B. The third communication I / F unit 120c is connected to the control device 20 via a signal line such as a LAN (Local Area Network) cable. The third communication I / F unit 120 c receives the data transmitted from the control device 20 and delivers it to the control unit 110, while transmitting the data delivered from the control unit 110 to the control device 20. Hereinafter, when it is not necessary to distinguish each of the first communication I / F unit 120a to the third communication I / F unit 120c, they are described as “communication I / F unit 120”.

  As illustrated in FIG. 4, the storage unit 130 includes a volatile storage unit 132 and a nonvolatile storage unit 134. The volatile storage unit 132 is, for example, a RAM (Random Access Memory). The volatile storage unit 132 is used by the control unit 110 as a work area when executing the relay control program 134a. In addition, the volatile storage unit 132 temporarily stores data received from each of the first communication I / F unit 120a, the second communication I / F unit 120b, and the third communication I / F unit 120c. And a role of a transmission buffer for temporarily storing data transmitted from each of the first communication I / F unit 120a, the second communication I / F unit 120b, and the third communication I / F unit 120c. Fulfill. The transmission buffer corresponding to each communication I / F unit 120 is provided for each transmission type such as a transmission buffer for cyclic transmission and a transmission buffer for single message transmission.

  The nonvolatile storage unit 134 is, for example, a flash ROM (Read Only Memory). In addition to the above-described relay control program 134a, the non-volatile storage unit 134 stores a transfer determination criterion table 134b. FIG. 5 is a diagram illustrating an example of the contents stored in the transfer determination criterion table 134b. As shown in FIG. 5, the transfer determination criterion table 134 b includes a part or all of data transmitted from each of the plurality of networks connected to the network device 10 to the control device 20. Information indicating whether or not it is necessary to transfer to is written. For example, the record rec01 in the first row of the transfer determination criterion table 134b shown in FIG. 5 is a range of offset 0 and size 4 (unit is bytes) in the monitoring data received from the IO device 11 via the network 40A. This data is represented as data in the range of offset 0 to size 4 of data cyclically transmitted to all devices connected to the network 40B.

  The relay control program 134a is a program that causes the control unit 110 to execute data transfer control between the network 40A or the network 40B and the control device 20. The control unit 110 reads the relay control program 134a from the non-volatile storage unit 134 to the volatile storage unit 132 when the power (not shown) of the network device 10 is turned on or reset, and starts its execution. Each time the control unit 110 operating according to the relay control program 134a receives data via each of the first communication I / F unit 120a to the third communication I / F unit 120c, the data corresponds to the destination. A transmission task for transmitting data stored in the transmission buffer to a connection destination of the communication I / F unit 120 corresponding to the transmission buffer is transmitted while executing a reception task for writing to the transmission buffer of the communication I / F unit 120 Execute for each buffer.

  FIG. 6A is a flowchart illustrating a flow of processing executed by the control unit 110 in a reception task executed when data is received via the first communication I / F unit 120a. As shown in FIG. 6A, in this reception task, the control unit 110 stores in the transfer determination criterion table 134b whether or not part or all of the received data needs to be transferred to another network. A determination process SA100 is performed with reference to the contents. Specifically, when the transfer judgment criterion table 134b includes a record corresponding to the network through which the determination target data passes, the transmission source station, and the data type, the control unit 110 transfers the data to another network. Is determined to be necessary, and if the corresponding record is not included in the transfer determination criterion table 134b, it is determined that transfer is not necessary. The network, source station, and data type through which the data to be determined is passed may be specified by referring to the header portion of the data (for example, “IO network header” in FIG. 2), and a part of the received data Can be determined by referring to the offset and size stored as information about the transfer source in the transfer determination criterion table 134b.

  When the determination result of the determination process SA100 is “Yes”, the control unit 110 refers to the information regarding the transfer destination stored in the transfer determination criterion table 134b regarding the data determined to be transferable, and transfers the transfer destination. Network, destination station and transmission type. Next, the control unit 110 corresponds to a part of or all of the data determined to be required to be transferred to the transfer destination network and corresponds to the transmission type specified in the above manner (transmission determination criterion table). The information is copied to the storage area indicated by the offset stored as information on the transfer destination in 134b (SA110). Thereafter, the control unit 110 copies the data to the transmission buffer of the communication I / F unit (in this embodiment, the third communication I / F unit 120c) corresponding to the destination (SA120). On the other hand, when the determination result of the determination process SA100 is “No”, the control unit 110 executes the process of SA120 without executing the process of SA110. If a pointer indicating the storage location of data to be transmitted is used as the transmission buffer, the pointer may be rewritten instead of the copy.

  FIG. 6B is a flowchart showing the flow of processing executed by the control unit 110 in the transmission task for the transmission buffer for cyclic transmission of the second communication I / F unit 120b. As illustrated in FIG. 6B, the control unit 110 transmits the data stored in the transmission buffer to the connection destination of the second communication I / F unit 120b, and a certain time (cyclic transmission). The process SB110 that sleeps only for a time corresponding to the data transmission interval is repeatedly executed. Of the data transmitted from the control device 20 to the network 40B, data to be subjected to cyclic transmission is also written in the transmission buffer. Accordingly, in the cyclic transmission from the network device 10 to the network 40B in the present embodiment, among the data transmitted from the control device 20 to the network 40B, the data to be cyclically transmitted and the data transmitted from the network 40A to the control device 20 are transmitted. Among the received data, the data to be cyclically transmitted to the network 40B is merged (that is, the former and the latter are cyclically transmitted from the network device 10 to the network 40B.

As described above, every time the control unit 110 operating according to the relay control program 134a receives data transmitted from the network 40A to the control device 10, a part or all of the received data is received. It functions as a determination unit that determines whether or not it is necessary to transfer to another network with reference to the transfer determination criterion table 134b, and transfers part or all of the data determined to be transferable by the determination unit. It functions as a data transfer means for transferring to the network together with the data transmitted from the control device 20 addressed to the previous network.
The above is the configuration of the network device 10.

(B: Operation)
Next, the operation of this embodiment will be described.
The operation of the present embodiment is roughly divided into an operation at a preparation stage for starting actual operation of the control system 1 and an operation at an actual operation stage. Hereinafter, these two operations will be described.

(B-1: Operation in preparation stage)
In the preparation stage, the operation manager of the control system 1 first operates the support tool 30 to create system definition information related to the control device 20, the network device 10, the network 40A, and the network 40B. The operation manager operates the support tool 30 and creates an application program to be executed by the control device 20. Then, system definition information and application programs created using the operation manager and the support tool 30 are downloaded from the support tool 30 to the control device 20 and stored.

Next, the operation manager creates a transfer determination criterion table in the control device 20 in the following manner. The operation manager first confirms the source of each data that needs to be transmitted from the control device 20 to each network via the network device 10 in the case of a conventional control system. When the data is transmitted from another network to the control device 20, the operation manager registers the transmission source station, transmission type, offset, and size of the data in the transfer determination criterion table as information on the transfer source, The transmission destination station, transmission type, offset, and the like of the transfer destination are registered in the transfer determination criterion table as information regarding the transfer destination of the data. The operation manager downloads the transfer determination criterion table created in this way from the control device 20 to the network device 10 and stores it in the network device 10 as the transfer determination criterion table 134b.
In this way, the preparation for starting the operation of the control system 1 is completed.

(B-2: Operation after starting operation)
Next, the operation after the start of operation will be described by taking as an example the case where the transfer determination criterion table 134b shown in FIG.
The IO device 11 transmits the monitoring data detected by the sensor of its own device to the control device 20 via the network 40A. The control unit 110 of the network device 10 executes the reception task shown in FIG. 6A when the monitoring data is received via the first communication I / F unit 120a. The control unit 110 determines whether the monitoring data needs to be transferred to another network with reference to the transfer determination criterion table 134b (FIG. 6A: SA100).

  At the start of operation of the control system 1, the stored contents of the transfer judgment criterion table 134b of the network device 10 are as shown in FIG. Since the monitoring data transmitted from the IO device 11 matches the first record in the transfer determination reference table 134b, the determination result of the determination process SA100 in FIG. 6A is “Yes”. Therefore, the control unit 110 copies the data in the range of offset 0 and size 4 of the monitoring data to the transmission buffer for cyclic transmission of the second communication I / F unit 120b (FIG. 6A: SA110). Then, the monitoring data is copied to the transmission buffer of the third communication I / F unit 120c (FIG. 6A: SA120).

  The monitoring data stored in the transmission buffer of the third communication I / F unit 120c of the network device 10 is transferred to the control device 20 by the transmission task for the third communication I / F unit 120c. Similarly, data stored in the transmission buffer for cyclic transmission of the second communication I / F unit 120b of the network device 10 (the data in the range of the monitor data offset 0 and size 4 and transmitted from the IO device 12) The monitoring data offset 2, the data in the size 2 range, and the data transmitted from the control device 20 to the network 40B are cyclically transmitted to the network 40B by the transmission task shown in FIG.

  As a result of the operation described above, in the present embodiment, the monitoring data transfer path C1 (see FIG. 3) transmitted from the network 40A and transferred to the network 40B is the transfer path C0 (see FIG. 3) in the conventional control system. 7), it is shortened by an amount not following the path “network device 10 → control device 20 → network device 10”. For this reason, the transmission delay time related to the monitoring data transmitted from the network 40A and transferred to the network 40B is shortened, and a highly accurate system can be constructed.

  Further, according to the present embodiment, the processing load on the control device 20 is reduced as compared with the prior art by the amount that the network device 10 copies data transmitted from the network 40A and transferred to the network 40B. The That is, according to the present embodiment, it is possible to realize load distribution for the processing load of the control device 20.

  In addition, if the network device 10 is used so that operation can be continued even when the control device 20 fails, the following effects can be obtained. If the control system 1 is a conventional control system, the data transmitted from the network 40A cannot be transferred to the network 40B when a failure occurs in the control device 20. On the other hand, according to the present embodiment, it is possible to continue data transmission between the network 40A and the network 40B even during the failure of the control device 20. Thereby, for example, even if the control device 20 is out of order, the alarm information transmitted by the IO device 11 and the IO device 12 connected to the network 40A can be detected by the HCI device 23 connected to the network 40B. When it becomes possible, such remarkable effects are produced.

(C: deformation)
Although one embodiment of the present invention has been described above, it goes without saying that the following modifications may be added to this embodiment.

(1) Although the case where the network 40A is an IO network and the network 40B is a control network has been described in the above embodiment, the types of the network 40A and the network 40B are irrelevant to the essence of the present invention. Therefore, both the network 40A and the network 40B may be IO networks, and both the network 40A and the network 40B may be control networks. The data transfer method in the network 40A or the network 40B is also irrelevant to the essence of the present invention. Therefore, any of a polling method, a cyclic transmission method, and a message transmission method may be adopted as a data transfer method in the network 40A or the network 40B.

(2) In the above embodiment, the case where two networks are connected to the network device 10 has been described. However, a mode in which three or more networks are connected to the network device 10 may be used. The transfer destination of the received data may be a plurality of networks. For example, a mode in which the network 40A, the network 40B, and the network 40C are connected to the network device 10 and data received from the network 40A is transferred to both the network 40B and the network 40C may be used.

(3) In the above embodiment, the relay control program 134a is stored in advance in the non-volatile storage unit 134 of the network device 10 by causing the control unit 110 to execute processing that clearly shows the features of the present invention. However, the relay control program 134a may be distributed by being written on a computer-readable recording medium such as a CD-ROM (Compact Disk-Read Only Memory), or by download via a telecommunication line such as the Internet. May be. By operating a control unit (computer such as a CPU) of a general network device in accordance with the relay control program 134a distributed in this way, the network device can function as the network device of the present invention. Because. In the above embodiment, the determination unit and the data transfer unit are realized by software modules, but may be realized by hardware modules. Specifically, each of the determination unit and the data transfer unit may be configured by an electronic circuit, and the network device of the present invention may be formed by combining these electronic circuits.

(4) In the above embodiment, the transfer determination criterion table is created in the control device 20 at the time of system definition / application registration, and the transfer determination criterion table thus created is transmitted to the network device 10 and stored. However, the transfer determination reference table may be created in the support tool 30 at the time of system definition / application registration, and transmitted from the support tool 30 to the network device 10 via the control device 20 and stored. May be stored in the control device 20, transmitted from the control device 20 to the network device 10 at the start of operation, and stored in the network device 10.

DESCRIPTION OF SYMBOLS 1 ... Control system, 10 ... Network apparatus, 11, 12 ... IO apparatus, 20, 21, 22 ... Control apparatus, 23 ... HCI apparatus, 30 ... Support tool, 40A, 40B ... Network, 110 ... Control part, 120a ... 1st 1 communication I / F unit, 120b ... 2nd communication I / F unit, 120c ... 3rd communication I / F unit, 130 ... storage unit, 132 ... volatile storage unit, 134 ... non-volatile storage unit, 134a ... relay control Program, 134b ... Transfer judgment criteria table, 140 ... Bus.

Claims (4)

A control device comprising: a control device; and a relay device connected to the control device and connected to a plurality of networks, and transferring data transmitted from each of the plurality of networks to the control device to the control device. A system,
The relay device is
A transfer criterion table in which information indicating whether or not part or all of data transmitted from each of the plurality of networks to the control device needs to be transferred to another network is written;
Whether or not it is necessary to transfer a part or all of the received data to another network every time data transmitted from each of the plurality of networks to the control device is received. Determination means for referring to a table;
Data transfer means for transferring a part or all of data determined to be required to be transferred by the determination means to the network together with data transmitted from the control device to a part or all of the transfer destination network. And a control system characterized by comprising: A transmission buffer corresponding to each of the plurality of networks;
The data transfer means includes
A part or all of the data determined to be transferable by the determination means is written in a predetermined storage area of a transmission buffer corresponding to the transfer destination network, and the data transmitted from the control device to the network is The control system according to claim 1, wherein the control system writes to a storage area different from the storage area and transmits the stored contents of the transmission buffer to the network at a predetermined timing. A transmission buffer corresponding to each of the plurality of networks is provided for each type of data transmission to the network,
The determination means determines whether or not part or all of the received data needs to be transferred to another network, and determines a transmission type at the time of transfer,
The data transfer means includes
Writing a part or all of the data determined to be required to be transferred by the determination means to a predetermined storage area of the transmission buffer corresponding to the transfer destination network and corresponding to the transmission type determined by the determination means. The control system according to claim 2. A relay device connected to the control device and a plurality of networks, and transferring data transmitted from each of the plurality of networks to the control device;
A transfer criterion table in which information indicating whether or not part or all of data transmitted from each of the plurality of networks to the control device needs to be transferred to another network is written;
Whether or not it is necessary to transfer a part or all of the received data to another network every time data transmitted from each of the plurality of networks to the control device is received. Determination means for referring to a table;
Data transfer means for transferring a part or all of data determined to be required to be transferred by the determination means to the network together with data transmitted from the control device to a part or all of the transfer destination network. A relay apparatus comprising: and.

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