JPH04109303A - Adjustment controller - Google Patents

Abstract

PURPOSE:To minimize the influence of a device failure upon a plant and allowing this adjustment controller to contribute to the safety operation of the plant by providing the controller with a backup logic circuit. CONSTITUTION:Since a digital output substrate 11 is turned off when the controller 1 is abnormal, an operation output 7 is switched to a set signal 16. The normality diagnosis of an analog output substrate (AO) 12 detects a substrate failure by reinputting the self-diagnosis (OS) of the substrate and an answer back signal 13 of a controller output signal 12 to the controller 1 and deciding whether an output requested by the controller 1 is generated or not. Namely, an output allowance error epsilon is set up while considering an error in the analog part of the AO 12, an error in the analog part of an analog input substrate(AI) 5 and a bit lacking error at the time of A/D conversion. Abnormality is detected by the following expression. ¦(AO output value) - (answer back value)¦<=epsilon.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides an adjustment control system in which the arithmetic processing section that performs the arithmetic processing of a plurality of loops is duplicated, and the process input circuit is single-layered. Regarding equipment.

(Prior Art) FIG. 2 shows an example of an adjustment control device having a conventional 2 CPU-IPI10 system (duplicated central processing unit, single process input circuit configuration).

In FIG. 2, the controller 1 has two CPUs 2. Each CPU 2 is connected to a PI 10 unit 4 by a system bus 3. Controller 1 is
Input the reprocessing amount 10 from the analog input board (AI) 5, perform processing such as PID calculation on this value, and output the operation output cuff from the analog output board (AO) 6 to the control valve 8 installed in the piping 9. do.

In such a 2 CPU-IP I102 dual configuration configuration groove device, the reliability of the P I10 section is extremely high compared to the CPU section, and the influence of abnormalities is small in the loop per board. is one layer. On the contrary, CP
U generally controls multiple control loops, and C
Since there is a possibility that a PU going down may cause the plant to stop, a redundant system is used to increase reliability.

However, if P Ilo, which is highly reliable, had a single layer, there would be no backup in the unlikely event of a failure, and although the plant would not be shut down, a decline in plant operation efficiency was unavoidable.

(Problems to be Solved by the Invention) In general, important regulation control devices are made multiplexed in order to prevent plant trips due to control unit failures, and the reliability of the control devices is improved. However, the device cost is high and all The problem is that it cannot be applied to the system.

However, as mentioned above, the conventional 2 CPU-1 PI10
The redundant control device solves the above problem, but the IPIlo
There is a high possibility that a malfunction will lead to a decline in plant operation.

The present invention moves the plant to a fail-safe direction by switching the output to the setting device when the controller is down, and in the case of a single analog output board failure, inputs the operation output as an answer back and self-diagnoses the 8-power board failure. In addition, we have taken measures in the application software to improve the reliability of board failure detection, and when a board failure is detected, the operation output is transferred from the controller output to the setting device, and the operation end is outputted with preset values including fail-safe directions. The aim is to minimize the impact on equipment, increase the time margin for troubleshooting and maintenance, and solve both the problem of equipment costs and the problem of reduced availability.

[Structure of the invention]

(Means and actions for solving the problem) Single layer P I1
In order to detect a failure in part 0, in addition to self-diagnosis, the AO answerback is input to the AI for monitoring. It also has a manual setting device that outputs a preset manipulated variable to shift the control loop toward safety in the event of an AD failure. The output of the controller and the output of the manual setting device are sorted by an output signal switch and output to the control valve. The output of the output signal switch is normally the controller output side, and when a 2CPU abnormality or a failure of the AO or AI board is detected by self-diagnosis, or when there is a large deviation between the A○ command and the AO answerback signal mentioned above, the output signal is switched to the manual setting device side. The output is The setting value of the manual setting device is a fail-safe value or a value of 10 obtained in advance through tests, etc.
The operating output value, etc. during 0% load operation shall be set to minimize the impact on the plant. This will prevent the CPU from
Even in the event of a failure or failure of the PI 10, significant margin for troubleshooting or maintenance time can be obtained.

(Embodiment) An embodiment of a regulating device having an output backup means according to the present invention is shown in FIG.

The controller 1 is a system in which the CPU 2 is duplicated. CPU of controller 1 that controls multiple loops
2 and the PI10 unit 4 are connected by a system bus 3. Inside the P I10 unit 4, there is a process amount of 10
and an analog input board (AI) 5 for inputting the controller output answer back signal 13, an analog output board (AO) 6 for outputting the controller output signal 12 which is the control calculation result of the controller 1,
The switching signal 18 is sent to the output signal switching device 17 based on the diagnosis result of
A digital output board (D◯) 11 that outputs is housed.

The output signal switch 17 has a controller output signal 12 that is output as a manipulated variable cuff to the control valve 8 installed in the piping 9 when the controller 1 and analog output board (AO) 6 are normal, and a setting device that is output when there is an abnormality. 15 setting signals 16
are input, and these two signals are selected and output by the switching signal 18.

Also, at the time of recovery, controller output signal 12 and setting signal 1
An output deviation indicator 14 is installed in order to check the balance of 6.

Next, the operation of this embodiment will be explained.

The digital output board (Do) 1.1 is set to ON operation when the controller 1 and analog output board (AO) 6 are normal. Assuming that the controller output signal 12 is output when the controller is ON, when the controller 1 is abnormal, the digital output board 11 is turned OFF and the operation output signal 16 is switched to the setting signal 16.

Normal diagnosis of the analog output board (AO) 12 is performed by re-inputting the board's self-diagnosis (OS) and the answerback signal 13 of the controller output signal 12 to the controller 1, and determining whether the output required by the controller 1 is being made. Detect failure. As a method of determination, the analog output board (A
O) 1.2 analog part error, analog input board (A
I) Set the output tolerance ε by taking into consideration the error in the analog section of 5 and the error due to bit loss during A/D conversion. Based on this E, an abnormality is detected as follows.

(AO output value) - (answerback value) 1≦ε Also, the setting device 15 determines the settings in advance. The setting method is to set the fail-safe direction of each control loop, and to check the setting corresponding to the valve opening of control valve 8 in the plant's 10-day operating state during a trial run test or plant patrol. There is a method to set this.

As explained above, according to this embodiment, the influence on the plant can be minimized in case of a double CPU failure or an AO board failure of the adjustment control device, and the time margin for troubleshooting and restoration work can be greatly improved. I can do it.

In the embodiment shown in FIG. 1, the installation location of P Ilo is
The same effect can be obtained by installing the PIlo at the same location as the remote PI 10, or by installing the PIlo as a remote PI 10 near the equipment installation location other than the central operation room.

Further, although an example has been shown in which the diagnosis of the operation output is performed by the CPU that performs the control, it can also be performed by a separate CPU or failure diagnosis logic.

〔Effect of the invention〕

By providing a backup logic circuit in the unlikely event of a malfunction in the redundant regulation control device that controls multiple loops, the impact of equipment failure on the plant can be minimized, and the time required for troubleshooting and maintenance can be reduced. This can contribute to the stable operation of the plant.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the *i control device having output backup means according to the present invention, and FIG. 2 is a block diagram showing a conventional adjustment control device. 1... Controller 2... CPU3...
System bus 4...P engineering 10 units 5...
・Analog input board (AI) 6...Analog output board (AO) 7...Manipulation output 8...Control valve 9...
Piping 10... Process amount 11...
Digital output board (Do) 12... Controller output signal 13... Controller output answer back signal 14...
・Output deviation indicator 15...Manual setting device 16...
・Manual setting signal 17...roka signal switch】8
・Switching Signal Agent Patent Attorney Noriyuki Chika Diagram Diagram

Claims (3)

[Claims] (1) In an adjustment control device equipped with a controller that takes a process quantity as input and controls a specific process quantity to a target value, the controller output from this controller and the setting signal from a setting device are input, and the abnormality diagnosis result of the controller output is an output signal switcher that switches the two outputs based on a switching signal based on the switching signal and outputs the switched output as an operation output to the controlled device;
It is equipped with an analog input board that inputs the controller output as an answerback signal, and a digital output board that outputs a switching signal to the switching device, and is capable of performing a fail-safe output set in advance by a setting device to the controller in the event of an abnormality in the controller or to the controller. Features an adjustment control device. (2) The adjustment control device according to claim 1, wherein the setting device is a manual setting device capable of performing a backup operation excluding a controller. (3) The adjustment control device according to claim 1, further comprising an output deviation indicator that inputs the controller output and the setting device output.