JPH08179816A - Distributed control system - Google Patents

Abstract

PURPOSE: To provide a distributed control system with which the interruption of process control can be suppressed to a minimum as much as possible in the case of abnormality analysis and abnormality can be sufficiently accurately analyzed. CONSTITUTION: Data are collected at high speed by a data collecting part 11 and stored in a logging memory 14 while deciding abnormality with an abnormality deciding arithmetic part 15. When there is no abnormality, arithmetic is performed in a normal sampling cycle by an arithmetic part 12, normal control is performed, and data are transferred from a communication switching I/F part 16 to another device in a fixed cycle. When an abnormality is decided, the data in the logging memory 14 are transferred through the communication switching I/F part 16 to an operation control part 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed control system for process control and the like.

[0002]

2. Description of the Related Art A conventional distributed control system used in process control includes a plurality of arithmetic control units 1 as shown in FIG.
0 _-1 , ..., 10 _-n and at least one operation control unit 20 (which may be plural) are connected by a communication line 30. Each arithmetic control unit 10 _-1 , ...,
Each of 10 _-n takes in an analog or digital signal, performs a predetermined calculation independently, and outputs the calculation result. The operation control unit performs system abnormality analysis and the like. The arithmetic control units 10 _-1 , ..., 10 _-n and the operation control unit 20 regularly exchange data with each other.

[0003]

In the conventional distributed control system described above, when performing anomaly analysis by data logging in the operation control unit, the number of control signals, that is, the number of samplings and the limit of the communication speed, causes a short period of time. However, there is a problem in that the detailed data of the above cannot be transferred from each operation control unit to the operation control unit, and the operating state when an abnormality occurs cannot be analyzed in detail in terms of time.

Further, in order to perform the operation analysis, it is necessary to construct another system by logging data in addition to the control system. The present invention has been made in view of the above problems, and provides a distributed control system capable of performing abnormality analysis with sufficient accuracy while minimizing interruption of process control for abnormality analysis. Is intended.

[0005]

DISCLOSURE OF THE INVENTION The distributed control system according to the present invention includes a calculation control section for fetching data for control at a predetermined sampling period, performing a predetermined calculation, and outputting a calculation result, and this calculation. In a device including an operation control unit that receives data transferred from the control unit and performs an abnormality analysis, etc., the operation control unit acquires data at a sampling cycle faster than the sampling cycle required for the operation. Means, data storage means for storing the fetched data, abnormality determination means for determining whether or not the data in the data storage means is abnormal, and normal operation if the abnormality determination means does not In the case of abnormality, means for selecting the transfer operation of the data of the data storage means to the operation control section is provided.

In this distributed control system, the arithmetic control unit takes in data at a speed higher than the sampling period required for the arithmetic operation, stores the data in the data storage means, and makes an abnormality determination based on the stored data. In a state where there is no abnormality, normal calculation control is executed in a normal sampling cycle, and data is also transmitted / received in a fixed cycle. When the abnormality determination means determines an abnormality, the data stored in the data storage means is transferred to the operation control section, and at the same time, the fixed cycle data transfer is switched to the non-fixed cycle data transfer from each arithmetic control section. , The operation control unit starts the abnormality analysis.

[0007]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a block diagram of a process control system showing an embodiment of the present invention. This process control system includes an arithmetic control unit 10, an operation control unit 20, and a communication line 30 connecting them. However, there may be a plurality of arithmetic control units 10 as shown in FIG. The operation control unit 20 is also the same.

The arithmetic control unit 10 includes a data collection unit 11 which receives analog data AI and digital data DI as inputs.
An arithmetic unit 12, a data output unit 13 that outputs analog data AO and digital data DO, a logging memory 14, an abnormality determination arithmetic unit 15, and a communication switching I / F unit 16
It has and. The operation control unit 20 includes a communication switching I / F unit 21, a memory 22, a disk 23, a data display unit 24, and a failure analysis unit 25.

In normal times, the data collecting unit 11 of the arithmetic control unit 10 fetches the data AI and DI at a high-speed sampling period, and the collected data AI and DI are passed to the arithmetic unit 12 at a sampling period several times as long as the data fetching. The arithmetic unit 12 performs various arithmetic operations, the arithmetic operation result is passed to the data output unit 13, and the analog data AO and the digital data DO are output. In this way, the sampling period for data acquisition is set to be much faster than the calculation sampling period.

The arithmetic unit 12 also sends the arithmetic result and control signals to other arithmetic control units to the communication switching I / F unit 16 to communicate with other systems at a fixed cycle. That is, data is exchanged. Further, the data collected by the data collection unit 11 is passed to the logging memory 14 at high speed, and the data is continuously stored in the ring buffer format.

When an abnormality occurs, when an abnormality is detected in the data in the logging memory 14 by the abnormality determination calculator 15 of each arithmetic controller 10, all nodes (each arithmetic controller, operation controller) are notified of the abnormality occurrence. , Communication switching I / F unit 16,
21 is instructed to switch. After that, the time-series data is transferred from the logging memory 14 of each arithmetic control unit 10 to the communication switching I / F.
The operation control unit 20 receives the signal via the unit 16 and the communication line 30.

Then, the communication switching I / F unit 21 and the memory 2
After 2, the data is stored in the disk 23 or the like. When all the logging data is received, the communication switching I / F units 16 and 21 are instructed to switch again to return to the normal state. The operation control unit 20 reads the stored data from the disk 23. Then, the failure analysis unit 25 performs abnormality analysis. Even when an abnormality occurs, the arithmetic unit 12 of the arithmetic control unit 10 is not stopped, and control is always performed continuously. However,
When performing loop control between multiple arithmetic control units, each arithmetic control unit holds the control state and immediately returns to the normal control state after the completion of data transfer when an abnormality occurs.

A normal control signal (reception data) received by communication from another arithmetic control unit is held at a value immediately before the occurrence of an abnormality, control is continued at that value, and the normal control state is immediately obtained after the completion of data transfer when the abnormality occurs. Recover to. I am trying.

[0014]

According to the present invention, since data is taken in at high speed and stored in the data storage means, high-speed logging is possible, and abnormality analysis and the like can be performed with high accuracy. Further, while the data is stored in the storage means at high speed, when the data is normal, the normal process control is performed, so that the process control and the data logging can be integrated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an internal configuration of a distributed process control system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a general distributed control system.

[Explanation of symbols]

 10 arithmetic control unit 11 data collecting unit 12 arithmetic unit 14 logging memory 15 abnormality determination arithmetic unit 16 communication switching I / F unit 20 operation arithmetic unit

Claims (1)

[Claims] 1. An arithmetic control unit for fetching data for control at a predetermined sampling period, performing a predetermined arithmetic operation, and outputting an arithmetic result, and receiving data transfer from the arithmetic control unit, and performing an abnormality analysis or the like. In a distributed control system including an operation control unit, the operation control unit includes a data acquisition unit that acquires data at a sampling cycle faster than a sampling cycle required for the operation, and a data storage that stores the acquired data. Means, an abnormality determining means for determining whether or not the data in the data storage means is abnormal, and a normal operation in the case where the abnormality is not detected by the abnormality determining means, and a data in the data storage means in the case of the abnormality. And a means for selecting a transfer operation to the operation control unit of the above.