JP2009080770A - Monitor and control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new monitor and control system capable of further shortening an update cycle of shared data among PCs and further speeding up data communication between each PC and each individual facility control PLC. <P>SOLUTION: In the monitor and control system 100 with a plurality of facility control PLCs 10 and a plurality of information processing terminals (PCs) 20 communicably connected, the plurality of facility control PLCs 10 are connected by a PLC network N1, the plurality of information processing terminals 20 are connected by a PC network N2, and the respective information processing terminals 20 are respectively connected direct to the PLC network N1 through respective dedicated relay PLCs 30. Thereby, the update cycle of shared data among the PCs 20 can be further shortened, and the data communication between each PC 20 and each individual facility control PLC 10 can be further sped up. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a computer monitoring and control system that is indispensable for realizing FA (factory automation) in production facilities and distribution facilities. Specifically, a plurality of facility control PLCs (programmable logic controllers) and a plurality of information. The present invention relates to a monitoring control system in which a processing terminal (PC) is communicably connected via a network.

2. Description of the Related Art Conventionally, as a computer monitoring control system that has been adopted in production facilities, distribution facilities, and the like, there is one having a configuration as shown in FIG. 6, for example.
As shown in the figure, this computer supervisory control system connects a plurality of facility control PLCs provided for each equipment of each facility by a PLC network so that they can be linked to each other, and a gateway PLC is connected to this PLC network. Connected to a personal computer network.

  Various types of data that change from moment to moment, such as the operating status of equipment controlled by each PLC for equipment control, are monitored in real time by a general-purpose personal computer (PC) connected to this personal computer network. Based on changes in the system, the operator can remotely control necessary equipment control PLCs, etc., and record / analyze these various data as needed to make further system and equipment improvements possible. ing.

Further, Patent Document 1 below discloses a facility operating status monitoring system having a configuration in which a dedicated monitoring PLC is installed between PLCs and PCs of a plurality of facilities.
In this monitoring system, first, the PLC of each equipment encodes signals such as the operating state, cycle time, and production number for calculating the operating rate, and the factor when the equipment has stopped abnormally, and monitors this as a BCD signal. Output to dedicated PLC. Next, the monitoring dedicated PLC that receives this BCD signal continuously monitors the PLC of each facility, calculates the collected data to the operating rate, etc., and sums it up to the stop history and the number of stops by factor / equipment. At the same time, the data is secured in the register and sent to the PC. A PC that receives these data takes these data into spreadsheet software, constantly monitors the operating state of the equipment, and creates daily and monthly reports and performs data analysis.
JP 2003-50624 A

  By the way, in the computer monitoring control system as shown in FIG. 6, a PLC network connecting a plurality of facility control PLCs is a dedicated network (LAN: Local) such as CC-Link (registered trademark). Since it is composed of (Area Network), it is possible to update data at a cycle of several milliseconds. However, since the personal computer network that connects PCs is composed of a general-purpose network such as Ethernet (registered trademark), the update period of shared data between the personal computers is limited to about 1 second at the shortest. It was.

In addition, in the case where each personal computer constantly distributes data that changes every moment to other personal computers, the communication frequency becomes enormous, resulting in further delays in data communication due to problems such as communication contention and PC load. was there.
In addition, since data communication between each personal computer and the gateway PLC is also performed via the personal computer network, an update cycle of about 1 second is the limit in order to prevent contention from occurring in these communications.

  Furthermore, in order to supply data between personal computers, it is necessary to add a special shared memory card, for example, a device such as Interface's Memlink (registered trademark) to each personal computer. When these special devices are used However, there are concerns that the same device cannot be obtained in the event of a future failure, or that it may not operate when the OS (Operating System) or communication protocol of the personal computer changes. In addition, since the PLC network and the PC network are connected by a single gateway PLC, if there is a problem such as a system failure or communication failure in this gateway PLC, communication between the two networks is complete. There is a problem that it stops.

On the other hand, in the monitoring system as shown in Patent Document 1, since the operation status of all the PLCs is monitored by one PC, the load is concentrated on one PC and this PC is temporarily assumed. If trouble occurs, monitoring may not be possible at all. In particular, in the case of a PC using a general-purpose OS such as Windows (registered trademark), the frequency of troubles tends to be higher than that of a PLC or the like using a state machine based on a relay circuit as an operation model.
Therefore, the present invention has been made in view of such problems, and its main purpose is to further shorten the update period of shared data between the personal computers, and to each of the personal computers and the individual equipment control PLCs. It is intended to provide a novel monitoring control system that can speed up the data communication.

In order to solve the above problems, the invention of claim 1
A monitoring control system in which a plurality of facility control PLCs and a plurality of information processing terminals are communicably connected to each other, wherein the plurality of facility control PLCs are connected via a PLC network, and the plurality of information processing terminals are connected to a PC. The monitoring control system is characterized in that each information processing terminal is directly connected to the PLC network via a dedicated relay PLC.
According to such a configuration, since each information processing terminal (PC) is directly connected to the PLC network via a dedicated relay PLC, there is no limitation on the communication speed of the PC network. Data communication with the equipment control PLC can be performed at high speed.

The invention of claim 2
2. The monitoring control system according to claim 1, wherein the relay PLC acquires data that changes every moment from the facility control PLC via the PLC network and the data acquisition unit. A monitoring control system comprising: data storage means for storing the received data; and data providing means for providing the data stored in the data storage means in response to a request from the information processing terminal.
According to such a configuration, the relay PLC acquires and accumulates (stores) data that changes every moment, and requests the information processing terminal (hereinafter referred to as “PC” or “PC” as appropriate). Since the data is appropriately provided according to the communication frequency, the communication frequency between the personal computer and each relay PLC can be reduced.
In addition, even when any one of the relay PLCs and personal computers has a trouble, it is possible to avoid a system down of the entire control system, a communication failure, or the like.

The invention of claim 3
The monitoring control system according to claim 2, wherein the relay PLC further includes a data transmission unit that transmits various data acquired by the data acquisition unit to another relay PLC via the PLC network. The data acquisition means is a supervisory control system characterized in that it also acquires data transmitted from another relay PLC via the PLC network.
According to such a configuration, data acquired by any relay PLC can be shared by all other relay PLCs via the PLC network. This eliminates the need to add a special device such as a shared memory card to each personal computer, so that stable operation and maintainability can be ensured in the future.

The invention of claim 4
The monitoring control system according to claim 2 or 3, wherein the relay PLC further includes a data monitoring unit that monitors a change in data stored in the data storage unit, and data monitored by the data monitoring unit. And a data notification means for notifying the information processing terminal when the value of the predetermined data changes or when the amount of change in the value exceeds a threshold value. is there.
According to such a configuration, since each information processing terminal can request transmission of the data only when notified from the relay PLC, the communication frequency between the personal computer and each relay PLC can be further increased. Can be reduced.

  In short, according to the present invention, data communication can be performed at high speed between each personal computer and the equipment control PLC. In addition, data sharing between personal computers, which has conventionally been possible only with an update cycle of about 1 second, can be shared with an update cycle of several milliseconds. Furthermore, since there is no need to add a special device, stable operation and maintainability can be ensured over a long period of time.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a configuration diagram showing an embodiment of a monitoring control system 100 according to the present invention.
As shown in the figure, this supervisory control system 100 includes a plurality (four in this embodiment) of PLC control networks 10, 10, 10, and 10 connected to each other so as to be capable of bidirectional communication. The information processing terminals (PCs) 20, 20, 20, and 20 are connected to each other so as to be capable of bidirectional communication, and each of these information processing terminals (PC). 20, 20, 20, 20 are connected directly to the PLC network N 1 via dedicated relay PLCs 30, 30, 30, 30.

  The PLC network N1 is configured by a dedicated local area network (LAN: controller network, field network, etc.) such as CC-Link (registered trademark) or MELSECNET (registered trademark), for example. Data update is performed in units of several milliseconds between 10, 10, 10 and the relay PLCs 30, 30, 30, 30.

  The facility control PLC 10 is a facility control computer for controlling each facility device. For example, a network unit for causing a base unit including a power supply unit, a CPU unit, an input / output unit, etc. Various devices according to control (information processing unit, analog unit, temperature control unit, temperature input unit, loop control unit, positioning unit, inter-channel insulation pulse unit, high-speed counter unit, interrupt unit), various devices such as memory cards Appropriate combinations are configured.

  On the other hand, the PC network N2 is configured by a general-purpose local area network (LAN) such as Ethernet (registered trademark). This general-purpose network uses TCP / IP (Transmission Control Protocol / Internet Protocol) as a communication protocol and adopts a communication method called CSMA / CD (Carrier Sense Multiple Access / Collision Detection). The update period of the shared data between 20 is about 1 second.

Each of these information processing terminals 20, 20, 20, 20 is composed of a general-purpose personal computer (PC) using a general-purpose OS (Operating System) such as Windows (registered trademark), for example, and system control is performed on this OS. Software (control program) is activated to monitor the entire facility, control individual devices, and acquire and manage various data that change from moment to moment, and other information processing terminals 20 and relays Data communication is performed with the PLC 30 for use.
Similarly to the equipment control PLC 10, the relay PLC 30 is a communication control computer (programmable logic controller: PLC) in which various units such as a power supply unit and a CPU unit are combined. The information processing terminals 20, 20, 20, and 20 are connected to the information processing terminals 20, 20, 20, and 20 via a compatible (general-purpose) LAN cable C so as to be capable of bidirectional communication.

  FIG. 2 shows a basic hardware configuration of each of the relay PLCs 30, 30, 30, 30. Various data are transferred between the information processing terminal 20 and the PLC network N1 as control signals. The input interface 31 and the output interface 32 that directly input / output data, the arithmetic unit 33 including a CPU, a memory (RAM), and the like, and a storage unit (ROM) that stores a control program and data.

  FIG. 3 shows the functions of each of the relay PLCs 30, 30, 30, 30 realized by the hardware configuration and the control program. The data acquisition unit 40, the data storage unit 41, the data Functions corresponding to the providing means 42, the data transmitting means 43, the data monitoring means 44, and the data notifying means 45 are realized.

Here, the data acquisition means 40 acquires various data that change every moment, such as operating states of various devices acquired by various sensors, from the PLC 10 for equipment control via the PLC network N1, and other data Various data transmitted from the relay PLC 30 via the PLC network N1 are also acquired and acquired.
The data storage means 41 stores / saves (accumulates) various data from the data acquired by the data acquisition means 40, and the data providing means 42 stores / saves (stores) the data in the data storage means 41. The accumulated data is provided (transmitted) in response to a request from the information processing terminal 20 that is paired with itself.

FIG. 4 shows an example of the flow of information processing by the relay PLC 30 realized by the data acquisition means 40, the data storage means 41, the data provision means 42, and the like.
As shown in the figure, first, when the relay PLC 30 acquires various data from the equipment control PLC 10 side in the first step S100, the relay PLC 30 moves to the next step S102 and stores / stores (accumulates) the acquired various data. Then, the process proceeds to the next step S104.
In step S104, it is then determined whether or not there has been a request for data provision from the information processing terminal (PC) 20. If it is determined that there is no request (No), the process returns to step S100 and continues to acquire various data. If there is a request (Yes), the process proceeds to the next step S106 to provide (transmit) the requested data to the information processing terminal (PC) 20.

That is, the relay PLC 30 not only stores / saves (accumulates) all the acquired information as it is and sends it to the information processing terminal (PC) 20 side, but also has a request from the information processing terminal (PC) 20 side. By selecting and providing only information, the information processing load on the information processing terminal (PC) 20 can be reduced.
Next, the data transmission means 43 transmits all of the various data acquired by the data acquisition means 40 or only one of the previously specified data to the other relay PLC 30 via the PLC network N1.

In other words, the data transmission means 43 transmits all of the data acquired by itself or data that is not acquired by other relay PLC 30 among the data acquired by itself to all other relay PLCs. All relay PLCs 30, 30, 30 can share the same data.
Accordingly, each of the relay control PLCs 30, 30, 30, 30 can be assigned to each equipment control PLC 10, 10, 10, 10, so that each relay PLC 30 required for monitoring and data acquisition can be shared. The processing load of 30, 30, 30 can be reduced.

The data transmission means 43 is also configured to transmit (distribute) the calculation results transmitted from the information processing terminal (PC) 20 to all the other relay PLCs 30, 30, 30. As a result, not only the data that changes every moment in each of the equipment control PLCs 10, 10, 10, 10, but also the data that changes every moment on the information processing terminal (PC) 20 side, all the relay PLCs 30, 30, 30,. 30, the same data can be shared. In addition, this data communication is performed very efficiently because the data update time is performed via the PLC network N1 having a unit of several milliseconds.
Next, the data monitoring unit 44 monitors (analyzes) changes in the data stored in the data storage unit 41, and the data notification unit 45 is configured to monitor the data monitored by the data monitoring unit 44. Among them, an event is issued (notified) to the information processing terminal (PC) 20 when the value of specific data registered in advance changes or when the amount of change in the value exceeds a threshold value It is.

FIG. 5 shows an example of the flow of information processing by the relay PLC 30 realized by the data monitoring unit 44, the data notification unit 45, the data acquisition unit 40, and the like.
As shown in the figure, first, when the relay PLC 30 acquires various data from the equipment control PLC 10 side in the first step S200, the relay PLC 30 proceeds to the next step S202 and analyzes the acquired data. In the next step S204, as a result of this analysis, it is determined whether or not the change amount of predetermined data set in advance exceeds the threshold value among the acquired data, and it is determined that it does not exceed (No). In step S200, the same process is repeated, but if it is determined that the process has been exceeded (Yes), the process proceeds to step S202, and an event is sent to the information processing terminal (PC) 20 that forms a pair to that effect. Issue.

Upon receiving this event, the information processing terminal (PC) 20 sends the data transmission request to the relay PLC 30 side, and the relay PLC 30 receiving the request responds to the request as shown in the flow of FIG. In response, the data is transmitted to the information processing terminal (PC) 20 side.
As a result, only the data required on the information processing terminal (PC) 20 side can be transmitted, so that the information processing load and communication traffic on the information processing terminal (PC) 20 side can be reduced.

As described above, the monitoring control system 100 of the present invention connects each information processing terminal (PC) 20, 20, 20, 20 directly to the PLC network N1 via the dedicated relay PLCs 30, 30, 30, 30. Thus, it is possible to perform data communication with each facility control PLC 10 at a high speed without being restricted by the communication speed of the PC network N2.
In addition, since data communication is performed via the PLC network N1 and data that changes from moment to moment is shared between the relay PLCs 30, 30, 30, and 30, the update cycle of only about 1 second is conventionally required. Data sharing between the information processing terminals (PCs) 20 that could not be performed can be performed with an update cycle of several milliseconds, and excellent information processing capability can be exhibited. Furthermore, since it is not necessary to add a special device such as a shared memory card for data sharing, the entire system can be stably operated over a long period of time and excellent maintainability can be ensured.

  Further, the data required for each information processing terminal (PC) 20, 20, 20, 20 is the information processing terminal (PC) when each information processing terminal (PC) 20, 20, 20, 20 is required. ) 20, 20, 20, 20 can be obtained by requesting the relay PLC 30 connected to the information processing terminal (PC) 20, 20, 20. , 20, for example, when it is desired to execute a specific process using a change in specific data as an event, the data change is detected by the relay PLC 30 and each information processing terminal (PC) 20, 20, 20 , 20 can be transmitted to the side of the information processing terminal (PC) 20 and the relay PLC 30.

Further, if a general-purpose PLC such as Melsec (registered trademark) is used as the relay PLC 30, 30, 30, 30, the general versatility of the entire system can be secured and the future maintainability is also improved.
Also, since the PLC network N1 and the PC network N2 are connected in parallel by a plurality of relay PLCs 30, even if a trouble occurs in any one of the relay PLCs or the information processing terminal (PC) 20. It is possible to avoid the worst case such as system down of the entire control system 100 or communication failure.

  In the present embodiment, each relay PLC 30, 30, 30, 30 and each information processing terminal 20, 20, 20, 20 are configured to be one-to-one, but the monitoring control of the present invention. In the system 100, if there are at least two relay PLCs 30, for example, two or more information processing terminals 20 are connected to one relay PLC 30, or one information processing terminal 20 is connected. The configuration may be such that two or more relay PLCs 30 are connected.

1 is an overall configuration diagram showing an embodiment of a monitoring control system 100 according to the present invention. It is a block diagram which shows the basic hardware constitutions of each PLC30,30,30,30 for relay. It is a functional block diagram which shows the concrete function of each PLC30,30,30,30 for relay. It is a flowchart figure which shows the flow of the data provision process implemented by each PLC30,30,30,30 for relay. It is a flowchart figure which shows the flow of the data notification process implemented by each PLC30,30,30,30 for relay. It is a general view which shows the structural example of the conventional computer monitoring control system.

Explanation of symbols

100 ... Supervisory control system 10 ... PLC for equipment control
20 ... Information processing terminal (PC, PC)
30 ... PLC for relay
DESCRIPTION OF SYMBOLS 40 ... Data acquisition means 41 ... Data storage means 42 ... Data provision means 43 ... Data transmission means 44 ... Data monitoring means 45 ... Data notification means N1 ... PLC system network N2 ... PC system network C ... Communication cable

Claims (4)

A monitoring control system in which a plurality of facility control PLCs and a plurality of information processing terminals are connected to be communicable,
The plurality of facility control PLCs are connected by a PLC network, and the plurality of information processing terminals are connected by a PC network.
A monitoring control system, wherein each information processing terminal is directly connected to the PLC network via a dedicated relay PLC. The monitoring control system according to claim 1,
The relay PLC is
Data acquisition means for acquiring data that changes every moment from the equipment control PLC via the PLC network;
Data storage means for storing data acquired by the data acquisition means;
A monitoring control system comprising data providing means for providing data stored in the data storage means in response to a request from the information processing terminal. The monitoring control system according to claim 2,
The relay PLC is
Further comprising data transmission means for transmitting various data acquired by the data acquisition means to another relay PLC via the PLC network;
The monitoring control system, wherein the data acquisition means is also configured to acquire data transmitted from another relay PLC via the PLC network. In the supervisory control system according to claim 2 or 3,
The relay PLC further includes data monitoring means for monitoring changes in data stored in the data storage means;
Data notification means for notifying the information processing terminal when the value of predetermined data among the data monitored by the data monitoring means changes or when the amount of change in the value exceeds a threshold value. A supervisory control system characterized by comprising.

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