JPS61275902A - Process control system - Google Patents

Abstract

PURPOSE:To confirm operations of switching parts by giving a switching signal to each switching part from an auxiliary controller and checking data obtained through the switching part. CONSTITUTION:An auxiliary controller 2 outputs a switching signal CD2 for a prescribed time periodically during holding. This switching signal CD2 is given to switching parts 4-6, and switching parts 4-6 select an output B of the auxiliary controller, a signal D from an input part 8, and an output G(B) of the switching part 4 respectively by the signal CD2. The output B of the auxiliary controller 2 is read through switching parts 4 and 6 as the result, and the auxiliary controller 2 compares outputted data (B) with read-in data (G), and the auxiliary controller 2 discriminates whether switching parts 4 and 6 are normal or not according as they coincide with each other or not.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a process control system that includes a main controller and a backup controller that backs up the main controller.

[Conventional technology]

Such process control systems generally include a switching section for switching process inputs and outputs from one controller to another, but this is required to operate reliably during switching. Conventionally, this problem has been dealt with by making this part highly reliable and nearly maintenance-free, or by having maintenance personnel perform periodic preventive maintenance.

[Problem that the invention seeks to solve]

However, while the former method has limitations due to cost or technical constraints, the latter method has the problem of increased preventive maintenance costs.

Therefore, an object of the present invention is to easily and inexpensively realize high reliability of a switching section that constitutes a process control system.

[Means for solving problems]

A main controller, a backup controller that backs up the controller, a data transmission line that exchanges control data between these controllers, and a switching signal that is output at predetermined intervals from the main controller when an error occurs or when the backup controller is on standby. a first switching section that switches the output from the main controller to the standby controller; a second switching section that similarly switches the input from the process to the standby controller; and a second switching section that similarly switches the input from the process to the standby controller; A third switching section that leads to the side is provided.

[Effect]

The preliminary controller provides switching signals to each of the switching sections and checks the data obtained through each of these switching sections to confirm the operation of the switching sections. Note that this is performed at predetermined intervals for a predetermined period of time while the standby controller is on standby.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the invention. In the figure, 1 is a main controller (MC), 2 is a standby controller (Be), 3 is a data transmission path, 4, 5, 6 is a switching section, 7 is an output section, and 8 is an input section. Further, the main controller 1 is composed of a control section 11, a data transmission section 12, a detection section 13, etc., and the auxiliary controller 2 is composed of a control section 21, a data transmission section 22, a waveform shaping section 23, etc.

The operation shown in FIG. 1 will be explained below with reference to FIG. 2 as well.

During normal operation, the main controller 1 performs predetermined control calculations based on data from the input section 8 and provides output data to the output section 7 via the switching section 4 . Therefore, the switching section 4 selects the large output of the main controller 1 as shown in FIG. 2(C), and the output E of the switching section 5 is turned off as shown in FIG. 2(D). At this time, the control data from the main controller 1 is given to the backup controller 2 via the data transmission line 3, so that the backup controller 2 is always ready for switching.

Here, if some kind of failure occurs in the main controller 1, the detection section 13 detects this and outputs an abnormality signal CD1 as shown in FIG. 2 (b). This abnormal signal CD1 is transmitted to the switching unit 4.
and the switching unit 5, the switching unit 4 switches from the output A of the main controller 1 to the output B of the auxiliary controller 2, as shown in FIG.
Accept input from other sources. On the other hand, the above-mentioned abnormality signal CD1 is directly applied to the control section 21 of the standby controller 2, thereby performing backup as shown in FIG. 2(E).

In order to improve the reliability of the switching sections 4, 5.6, their operation is checked as shown in FIG. In addition,
FIG. 3 is a time chart for explaining the check operation in FIG. 1.

This is performed by the standby controller 2 when the main controller 1 is normal as shown in FIG. 3(a), that is, when the standby controller 2 is on standby. That is, during standby, the standby controller 2 outputs the switching signal CD2 as shown in FIG. 3(b) for a predetermined period of time. This switching signal CD2 is given to the switching section 4.5.6,
As a result, the switching section 4 receives the output B of the standby controller as shown in FIG. 3(C), the switching section 5 receives the signal from the input section 8 as shown in FIG. 3(D), and the switching section 6 receives the signal from the input section 8 as shown in FIG. The output G (B) of the switching section 4 is selected as shown in (e). As a result, the backup controller 20 output B is read through the switching units 4 and 6, so the backup controller 2 compares the output data (B) and the read data (G) and finds that they match. The switching unit 4, depending on whether
6 is normal or not. This is based on the basis that if the switching unit 4.6 is normal, the data should match. Similarly, the signal from the input unit 8 is read by the main controller 1 and given to the backup controller 2 via the data transmission unit 12, so the backup controller 2 transmits this data (D) and the switching unit 5 to the backup controller 2. The operation of the switching section 5 is checked by comparing the input data (E) with the data (E) read from the input section 8. Note that during this check operation, the output B of the preliminary controller 2 is given to the output unit 7 as a disturbance, so the output time of the switching signal CD2 is adjusted by the waveform shaping unit 25 shown in FIG. B is adjusted so that it is approximately equal to the output value of the main controller 1, so as to avoid adversely affecting the process as much as possible.

〔Effect of the invention〕

According to this invention, since the operation of the switching section is checked from the standby controller while the main controller is normal, the reliability of the process control system can be easily and inexpensively improved without providing any special equipment for this purpose. This provides the advantages that can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a timing chart for explaining the backup operation in FIG. 1, and FIG. 5 is a timing chart for explaining the check operation in FIG. 1. be. Code explanation 1... Main controller (MCL 2...
... Spare controller j (BC), 3... Data transmission path, 4.5.6... Switching section, 7...
・Output section, 8... Input section, 11.21...
...Control unit, 12.22...Data transmission section, 13...Detection section, 23... Waveform shaping section.

Claims (1)

[Claims] A main controller, a backup controller that backs up the main controller, a data transmission path for mutually transmitting and receiving control data between these controllers, and a predetermined period from now on when an abnormality occurs in the main controller or while the backup controller is on standby. a first switching section that switches the output to the process from the main controller side to the standby controller side in response to a switching signal output from the switch; a second switching section that similarly switches the input from the process to the standby controller side; a third switching unit that guides the output to the process to the standby controller side according to the switching signal,
Each time a switching signal is applied to each of the switching sections, the preliminary controller compares its output data with data read through the first and third switching sections to check the operation of the first and third switching sections; The main controller receives a value read from the process input via the data transmission path, and compares this with a value led through the second switching section to confirm the operation of the second switching section. process control system.