JP2002152235A - Autonomous distribution type control system and autonomous distribution type control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an autonomous distribution type control system that permits normal control operation for any faulty human machine device, even when one of human machine devices operating independently of each other causes faults. SOLUTION: The human machine device receiving a command from an operator confirms the presence of abnormity operation of all the other human machine devices and the presence of an output to an operation object before writing an operation command to a common memory. Thus, even when specific human machine device causes faults, the commanded human machine device attains the same operation as a normal operation, and contention of the command by the human machine devices can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decentralized autonomous control system for operating a control device, and more particularly to a human-machine device having no master device and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, a system for managing a plant by connecting a controller (control device) for controlling plant equipment and a human machine device for giving instructions to the controller to a network has been widely known.

[0003] As described in Japanese Patent Application Laid-Open No. H11-24709, a conventional plant control human-machine device is configured such that one human-machine device controls data output to a control device and rewrites a memory of a network control device. Control. Here, only one human-machine device (master device) can send a command to the control device, and the other human-machine devices (slave devices) perform message communication with the master device so that the contents of the memory can be read. There was a master-slave relationship in which operation commands were indirectly transmitted to the control device by sharing.

In addition, as disclosed in Japanese Patent Application Laid-Open No. Hei 5-189004, in order to reduce the CPU load, there is a method in which task control is performed using a common memory of a human-machine device in a master-slave relationship. Was.

[0005]

In the control of a large plant, it is required to have high reliability and to cope with long-term operation. In the prior art, a slave device of a human-machine device monitors a master device, and even if the master device becomes abnormal, one slave device takes over the master function according to the priority order. When the transition to the master device is completed, the operation to the control device becomes possible.

However, it is necessary to always confirm that the master device is normal at certain time intervals, and there is no guarantee that the master device is normal until it can be confirmed. If the master device becomes abnormal, the command that the operator tries to send to the plant's control target at this time is:
There is a problem that the master device does not exist until the slave device confirms the device abnormality of the master device and the master function completes the transition to another slave device.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. H11-203254, exclusive control is performed by excluding a master / slave relationship and writing and reading a shared process in the same area of a shared memory by a plurality of nodes. is there. According to this, since it is necessary for a plurality of CPUs to write data in the same location of the shared memory, there is a problem that the control device is complicated and the processing speed is hindered.

Further, when task control is performed using a common memory, it is necessary to separately perform procedures of registering a task, periodically monitoring the registered task, and executing the task if any task exists. In any of these cases, there is a problem that the responsiveness of transmission of control information is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems by providing a plurality of human machine devices connected to a control device via a network even when a specific human machine device becomes abnormal. It is an object of the present invention to provide an autonomous decentralized control method and system capable of speeding up and simplifying processing with a simple configuration without causing time loss from other human machine devices.

It is another object of the present invention to provide a control system capable of reducing a network load and a CPU load by eliminating the need to constantly monitor the device status between human machine devices.

[0011]

In an autonomous distributed control system according to the present invention, a control device and a human-machine device are connected to a network to transmit and receive data. As a communication means between these devices, a common memory is provided on a network, and communication is performed by rewriting the common memory by each device. In addition, human machine devices
It has a hardware configuration that always performs an abnormality check by a self-diagnosis function and terminates its own communication when a device abnormality occurs.

According to the present invention, before a human-machine device receiving a command from an input device communicates an operation command to a control device, all the other human-machine devices can operate normally or not.
Check the abnormal status and whether there is output to the same operation target.
Then, when there is no output from another normal human machine device to the same operation target, execution of its own communication is determined. Also, if there is an output from another machine device to the same operation target, it does not perform its own communication. This eliminates contention.

According to the present invention, since all the human machine devices have the same function, a specific one such as a master can be used.
It is not dependent on the operating state of the table. Further, since it is avoided that a plurality of human machine devices simultaneously send different control commands to one control target on a first-come, first-served basis, the actual operation of the control target does not differ from the control command. In addition, since it is not necessary to perform exclusive control when writing data on the shared memory, the processing can be speeded up and simplified. Furthermore, the responsiveness can be improved by communicating control information directly from each human machine device to the control device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described. In the plant control system of the present embodiment, a conflict prevention function that prevents simultaneous transmission of different operation commands from a plurality of operation human machine devices to the same control device is distributed to all human machine devices. That is, the master-slave relationship regarding the output information from the human machine device is made masterless, and information can be transmitted directly from the human machine device to the control device. In addition, by using the masterless operation, it is possible to eliminate an inoperable time due to a device abnormality of the master device. In addition, by eliminating unnecessary communication between human-machine devices for preventing contention, it is possible to improve the responsiveness of control information transmission.

An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows the overall configuration of an autonomous distributed plant control system. A plurality of network control devices 14 connected to the network 16, a plurality of control devices 15 connected thereto, a plurality of human machine devices 13
And the CRT 1 connected to the human machine device 13
1, an input device 12 such as a keyboard and a touch panel. CRT1 with touch panel function
1. Commands input to the human machine device 13 by the input device 12 such as a keyboard are transmitted to the network control device 14, the network 16, the network control device 14.
To the control device 15 via the The network control device 14 includes an inter-device common memory 14a whose contents are common among the network control devices.

Although the present embodiment does not depend on the connection form of the network, in the configuration like the network control device shown in FIG.
3 has a shared memory 14a.

FIG. 2 shows an area of the common memory. The common memory area 24 includes, for example, the network controller 2
1, 22, and 23 are allocated to the memory areas,
The writing area of each network control device is divided. The areas to which the network controllers 21, 22, and 23 can write are only their own areas in the common memory area 24. The other areas are allocated to other network control devices, and the contents are constantly transferred to each network control device at certain intervals by a communication task. The transfer interval of the memory by the communication task is variable depending on the characteristics of the control target. Thereby, the contents written to the memory by another network control device can be referred to.

These network control devices are connected to a human machine device 13 and a control device 15. For example, the CP connected to the network control device 21
When the memory area 24 on the common memory of the network control device 21 is rewritten by U, the network communication by transfer is performed, so that the network control device 22,
The same area of the memory area 23 is also rewritten.
By doing so, the CPU connected to the network control devices 22 and 23 can refer to the contents of the rewritten memory of the network control device 21.

FIG. 3 shows an example of the data structure of the common memory. The figure shows an example in which the control target is a thermal power plant, but the present invention is not limited to this. As shown in the figure, the common memory area is divided for each network control device, a flag indicating its own command status to the control target is prepared in the memory area for each network control device, and the same control is performed for each memory area. There is a target flag. If the own device is currently instructing, the flag is rewritten and the other device is referred to by transferring the memory.

The memory area 24 has a life / death counter. These are the network controllers 21, 22, 2
3 is constantly updated by the CPU of the human-machine device 13 and the control device 15. When these devices do not operate normally, the updating of the life / death counter stops, so that it is possible to determine that the device is in a device abnormality state by not increasing the counter.

FIG. 4 shows the difference between the flow of control information communication according to the prior art and the embodiment. In the prior art (a), the master device of the human-machine device is determined using the communication between the network devices shown in FIGS. 1 and 2, control information from the slave device is transmitted to the master device once, and This is a case where the control information is output by the device. On the other hand, in this embodiment (b), since the human-machine devices 13 are of the autonomous distributed type in which no master is determined, control information is transmitted from each of the human-machine devices to the target control device.

FIG. 5 is a flowchart showing the overall operation of the distributed autonomous control system according to this embodiment.
In step 51, the operator transmits a command for controlling the plant to the human machine device using the input device of the human machine device. In step 52, the human machine receiving the command confirms the operation state by comparing the life and death counter in the memory area of the other human machine on the common memory with the previous value. It is determined whether another human machine device is operating normally (step 53). If it is operating normally, the process proceeds to step 55,
If it is not operating normally, the signal output from the device is deleted (step 54).

In step 55, it is confirmed whether or not another human-machine device is currently sending a command to the control target to be operated by the operator, and the control information in the common memory area of the other human-machine device and the control device. . By referring to the memory area, it is possible to confirm whether or not there is a device that sends the same signal or a signal different from the others. If all are the same, no signal is sent from any device, but if the signal of one human machine device and the control device is different from the signal of the other device, a control command is issued from that human machine device become. If another device is issuing a control command, a message to that effect is transmitted to the operator on the operation CRT screen in step 56.

At the time when the human machine device receives the control command, if another human machine device has not issued a command to the same control target, the memory on the common memory in the network control device is rewritten in step 57. At the time of rewriting, the memory area of the network control device connected to the target control device is rewritten (step 58). As a result, the control command issued by the operator to the control target using the human machine device is transmitted to the control device.

When a command is being issued by another human machine, the common memory is not rewritten by the newly operated human machine. This allows
The conflict that two or more human-machine devices control the same control device at the same time can be avoided, and the intention of the operator and the operation of the actual control target coincide.

When the control method shown in FIG. 5 is used, a human-machine device having a specific function called a master machine does not control the output to the control device, but outputs each other among all the human-machine devices. Are mutually checked, so that a control command can always be sent to a control target from a normal human machine device without depending on a certain device state.

FIG. 6 is a flow chart when the human machine device that has received the operator's command and the other human machine devices are both operating normally and are not currently outputting a signal. The human machine device 13 of the embodiment has a well-known RAS function in order to prevent outputting an erroneous signal and to stop data transmission in the event of a device abnormality. In step 61, the device abnormality is constantly monitored.
In step 62, the human machine device receives a control command from the input device. The device abnormality is monitored also in other human machine devices, and if the device is abnormal, the communication is stopped. Further, the information of the life and death counter is reflected in the common memory (step 63). In step 64, the human machine device that has received the command checks the life and death counter of another human machine device. At this time, the life and death counter of the other device is constantly updated on the common memory, and the counter value is different from the previous value. If the other device is operating normally, it is confirmed in step 66 that another human machine is not currently sending a signal to the control target of its own control command. At this time, the command of another device on the common memory which is rewritten in step 65 is referred to. Based on the information, the human machine receiving the command transmits the operation information to the control device to be controlled by rewriting a specific area on the common memory in step 67.

FIG. 7 is a flow chart when there is an abnormal operation state in other human machine apparatuses. The life and death counters of the other devices are checked as in the case of FIG. At this time, the function of step 61 does not update the life and death counter in step 71. Since the counter is not updated, the device abnormality of another device is detected. Since the device is abnormal, if there is a signal sent from the human machine device having the device abnormality to the control device in step 62, the signal is canceled, and the human machine device that has received the command transmits a new signal to the control device.

FIG. 8 is a flow chart in the case where there is a device which has already been operated on the same control target among devices other than the human-machine device which has been newly instructed. As in the case of FIG. 6, the life and death counters of the other human machine devices are checked in step 64. In order to avoid sending two or more commands to one control target at the same time, it is confirmed in step 66 that no other human machine device is in command. In this case, as a result of referring to the command of another device on the common memory which is rewritten in step 65, the other device is in the process of issuing a command. The information is displayed on the human-machine device that receives the command from the operator, and no new signal is sent to the control device.

According to the present embodiment, unlike the conventional master / slave configuration, all human-machine devices are configured to be autonomously distributed, so that there is no time for transition of the master function and commands are always sent to the control device. I'm ready. That is, it has high reliability that a command can always be sent. In addition, a signal can be exclusively transmitted to the control device in spite of a plurality of human machine devices.

Even if the operating time of each human machine device is short, stable operation can be performed if at least one of the plurality of human machine devices is operating. As a whole, it can support long-time operation.

Further, since there is no need to communicate control information between human-machine devices, the responsiveness of control information transmission is improved. Further, since it is not necessary to perform communication between human machine devices at certain time intervals, the network load can be reduced.

Based on these functions and effects, the present invention is applied to a plant configured by a human-machine device in which an operator issues a control command from a plurality of devices, and a control device that receives the command and controls a control target. As a result, the required high reliability and long-time operation can be achieved.

[0034]

According to the present invention, a normal operation can be performed even when a specific device becomes abnormal in a plurality of human machine devices connected to a control device via a network, and a self-contained distributed control can be performed. realizable. Further, since unnecessary communication between the master and the slave is not performed, the network load can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an autonomous distributed control system according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a common memory of the network control device.

FIG. 3 is an explanatory diagram of a data configuration example of a common memory.

FIG. 4 is an explanatory diagram showing a difference between the conventional art and the present embodiment.

FIG. 5 is a flowchart showing an autonomous distributed control method according to the embodiment.

FIG. 6 is a flowchart for each device in a normal state.

FIG. 7 is a flowchart for each device when another device has a device abnormality.

FIG. 8 is a flowchart for each device when another device is instructing.

[Explanation of symbols]

11: CRT display device, 12: input device, 13: human machine device, 14: network control device, 14a
... Common memory between devices, 15 ... Control device, 16 ... Network transmission path, 21, 22, 23 ... Network control device, 24 ... Common memory of network control device.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) G06F 13/00 351 H04L 11/00 320 5K032 H04L 29/14 13/00 311 5K035 F term (reference) 5B034 AA04 DD02 5B042 GA10 GB06 JJ04 JJ15 KK04 5B089 GA12 JA11 JB16 KA06 KA07 KA12 KB04 KC05 KC47 MC01 MC11 5H209 AA01 BB01 CC01 CC09 CC13 DD04 DD08 EE11 GG06 GG08 SS02 SS04 SS07 TT05 5H215 AA01X01 C03 CC11 CCA1 EA03 EB08 5K035 AA03 BB03 CC10 DD01 FF04 HH02 HH07 JJ02 KK02 LL01 MM02 MM03

Claims (3)

[Claims] A plurality of control devices for controlling a control target;
A plurality of human machine devices that transmit control information according to the state of the control target to the control device, and an autonomous distributed control system including a network control device that connects the control device and the human machine device to a network, In each of the network control devices, a common memory in which storage contents are shared is provided, and the human machine device checks the common memory when receiving control information from an input device, and all other human machines The apparatus is characterized in that it has a function of determining whether the apparatus is outputting control information to the same control target and writing control information addressed to itself to the common memory when control information from another apparatus is not being output. Autonomous distributed control system. 2. The human machine device according to claim 1, wherein a diagnostic function is provided in the human machine device, and when control information is received from an input device, all other human machine devices operate normally based on a result of each diagnostic function. An autonomous decentralized control system characterized in that it determines whether or not there is an error and discards the control information of the human-machine device having the abnormality. 3. A method for controlling a plurality of human-machine devices, wherein control information according to a state of a control target is transmitted to a control device via a common memory, wherein data is stored in a predetermined area of the common memory for each human-machine device. And each human-machine device monitors each other for device abnormalities, discards commands of abnormal devices, and transmits control information to the same control target on a first-come, first-served basis. Distributed control method.