JPS5958508A - Detecting method of abnormality in process control system - Google Patents

Abstract

PURPOSE:To detect abnormality all the time and to judge an abnormal part speedily by making a comparison between a flow rate detection signal and each predicted flow rate in such a state that an operation signal is higher than a set value, and detecting the abnormality. CONSTITUTION:A process control system supplies the operation signal MV to an operating valve 14 on the basis of the set pattern of a process variable to control the flow rate of fluid or flow rates from plural tanks. A controller, on the other hand, compares the flow rate detection signal PV from a flow rate detector 12 with preset predicted flow rates Q1-Q3. Then, a decision on the occurrence of abnormality to the controller 13 is made when the number of pulses of the signal PV is less than the beta of the predicted flow rate Q1 and a decision on the occurrence of abnormality to a flow rate transmission line 11 is made when below the beta of the predicted flow rate Q2; and a decision on the occurrence of abnormality to a transmission line for the flow rate detection signal PV is made when the number of pulses is less than the beta of the predicted flow rate Q2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for detecting an abnormality in a process control system that controls process quantities.

[Technical background of the invention and its problems]

Conventionally, a process control system that controls fluid flow, j:L', etc., is configured to detect the flow emitted by flow detection C:), detect and separate the The controller compares the flow rate settings shown in Fig. 2 with a controller, obtains an operating signal corresponding to the deviation, and controls the flow rate by applying this signal to the operating valve. Detection of an abnormality in the process control system of this process is performed at time t2 when a predetermined time tc has elapsed from the control start time t1 in flow rate setting P turn 1, or at time t3 when the maximum instantaneous flow rate fm has been reached. When the flow detected by the flow rate detector (the pulse rate of No. 1'i is the same as the maximum of setting pattern 1 ↑ Time flow J"lt
, If the number of pulses of the current detection signal at f m is less than the predetermined value α, it is determined that the pulse has not arrived and that there is an abnormality in the 70-process control system, not shown.
A 4'l report signal was generated from the L-report section.

Therefore, the abnormality detection method as described above is effective at a predetermined time t2. At time t3, the control signal is compared with flow rate setting pattern 1 to determine whether there is an abnormality in the process control system, so it is not possible to detect an abnormality until a certain period of time has elapsed after flow rate control started. There is a problem in that the presence or absence of an abnormality is not known, and the presence or absence of an abnormality is not always determined while detecting the flow rate, and in particular, when the controller is switched to manual mode, no abnormality is detected at all. Furthermore, even if a replacement alarm is issued, it is possible to completely disconnect the abnormality in any part of the process control system (e.g., flow rate detector, controller, control valve, or transmission line through which fluid flows). could not. Therefore, even if an abnormality occurs, there is a problem in that appropriate measures are delayed and the process control system is adversely affected.

[Purpose of the invention]

The present invention has been made to solve the above problems,
A process control system 11 that can detect whether the control I is in the white power mode or the manual mode (always in I), and can quickly determine the abnormal part in the event of an abnormality.
The purpose of this paper is to provide an abnormality detection method for 11 systems.

[Summary of the invention]

The present invention compares the detection signal from one process detector with a preset process quantity setting pattern, and controls the process quantity by operating the operating end according to the operating number corresponding to the deviation. Regarding the abnormality detection method of the process control system, is the operation signal used in the process? ii When the i4 pulse number of the detection signal is above or below a predetermined value corresponding to the normal operation and tracing operation of the control, itW @1 part is set in advance;
Determine whether the predicted value for each detector and process transmission line is less than or greater than a preset ratio β.
However, this is a method for detecting abnormalities in a process control system that aims to achieve the above object.

[Embodiments of the invention]

FIG. 2 is a diagram illustrating an embodiment of the present invention applied to a flow rate control system. In the figure, 11 is a fluid transmission path through which fluid flows, 12 is a flow rate detector, 13 is a controller, and 14 is an operating valve. The feature of the present invention is that the controller 10
1 means, specifically 6iC of the flow rate detector 12.
In addition to the means for obtaining the operation signal MV that compares the detection signal PV with the predetermined flow rate setting/turn and makes the deviation zero, the operation signal MV is also used as a means for determining the presence or absence of an abnormality. The predicted flow rate QJ=f(MV) determined based on the set value α of the operation signal MV, and the predicted flow rate Q determined based on the operation signal MV and the flow rate pressure P of the fluid transmission path 11, ?
= g (MY, P) and a predetermined flow rate Q3 determined based on the si4 fJl of the operation valve 4, and when the operation signal MV exceeds the set value α, the process detection signal pv
1! (not shown) when the number of pulses becomes less than the preset ratio β of the maximum flow rate of the set value Q1#Q2#Q3. The system detects the abnormality in each part of the process control system from the reporting section depending on the abnormality.

Next, we will discuss and clarify the method for detecting an abnormality in the process control system configured as described above. When the power is turned on, the process control system applies an operation signal MV to the operation valve 14 based on the process amount setting turn to control the flow rate of the fluid or the flow rate from the plurality of tanks. Thereby, the flow rate is sent according to a fixed pattern of the flow process as shown in FIG. 1, for example. Therefore, the process system i','IH
When Jp detects an abnormality in the system, it is performed as follows. First, in the case of normal DEb operation, it is assumed that the number of pulses of the operation signal MY exceeds a set value α at which detection of soldiers is detected. An abnormality is detected from this single point in 11. In other words, in the controller 13, the flow rate detector 1
A comparison is made between the detected signal PV and a preset predicted flow rate Q I P Q 21 Q ,9. As a result, if the flow rate +1 detection signal pv exceeds the set ratio β of the number of pulses corresponding to the pre-6:11 flow rate Q 1 , Q 2 t Q 3 , the control, ・11 It is determined that no abnormality has occurred in the system.

On the other hand, the number of noggles in the bin bl' detection signal pv decreases due to some reason. This means that
This means that the flow rate sent has decreased.

Therefore, in the controller 13, the following is determined based on the ratio (1) between the flow rate detection signal pv and the predicted flow rate Q1tQ21Q3.First, the number of pulses of the flow rate detection signal pv is determined based on the preset operation signal MV. Predicted flow rate QJ=f
(MV) is equal to or less than the set value β [crack]. In this case, the Noculus number of the flow rate detection signal pv is β of the predicted flow rate Q1 [
H) Since the following is true, it is determined that an abnormality has occurred in the J cylinder shaft 13.
A total of 13 warnings are issued to indicate that an abnormality has occurred.

Next, the number of pulses of the flow rate detection signals p and v is determined by the operation signal MV
It is assumed that the predicted flow rate determined based on the flow rate pressure P of the flow rate transmission line 11 is equal to or less than β of Q2=g(MV, P). In this case, since the number of pulses of the flow rate detection signal pv is less than or equal to β [chi] of the predicted flow rate Q2, it is determined that an abnormality has occurred in the flow rate transmission line 11. Then, in the same way as when an abnormality occurs in the adjustment section 13, the warning section issues a warning that an abnormality has occurred in the flow rate transmission line 11.

Next, it is assumed that the number of pulses of the flow rate detection signal pv is equal to or less than β of the predicted flow rate Q3 determined based on the opening degree of the operating valve 14. In this case, since the number of pulses of the flow rate detection signal pv is less than or equal to β of the predicted flow rate Q3, the flow rate (detector 12
Alternatively, it is determined that an abnormality has occurred in the transmission path of the flow rate detection signal pv. Then, an alarm is issued indicating that an abnormality has occurred in the transmission path of the flow rate detection signal pv by passing the flow 1 over the detector 12.

The abnormal operation described above is detected by the flow rate detection @' @ P V from the flow rate detector 12 and the predicted flow rate Q set in advance.
)+Q2pQ3.

Furthermore, abnormality detection is possible when the controller 13 automatically controls the flow rate or manually! This is done when the flow rate is controlled by i; iJ.

Furthermore, in the case of commuting, abnormal operation is detected from the time when the number of pulses of the operation signal M2 becomes equal to or less than the set value α. The abnormal operation is detected in the same manner as the normal operation.

Therefore, in a state where the operation signal MV is equal to or higher than the set value α, the constant flow rate detection signal pv and the predicted flow rate Q1pQ2. Qs
p anomaly is detected by comparing
It is possible to quickly determine which of the process control system controller 13, flow rate transmission line 11, flow rate detector 12, and flow rate detection signal pv transmission line has an abnormality.

Furthermore, even if the process is controlled automatically or manually, abnormalities can be detected.

〔Effect of the invention〕

The present invention detects an abnormality by comparing the flow rate detection signal and each predicted flow rate when the operation signal is equal to or higher than the set value α, so abnormalities can be constantly detected in either automatic mode or manual mode control. Accordingly, it is possible to provide an abnormality detection method for a 70-process control system that can quickly detect the cause of the abnormality.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a setting turn for performing process control, and FIG. 2 is a diagram showing a configuration of a process control system to which an abnormality detection method for a process control system according to the present invention is applied. 1... Settings )P turn, 12...Flow rate detector, 13
...Controller, 14...Operation valve.

Claims (1)

[Claims] In a process control system that compares a process detection signal from a process amount detection section with a preset process pattern using a controller and outputs an operation signal corresponding to the deviation to an operation section to control the process amount, When the signal exceeds or falls below a predetermined value according to the process amount control 9111, it is determined whether the number of pulses of the process detection signal is less than or equal to a preset number of seven pulses. How to know and judge the abnormal part of process control system 11? V Desired method for detecting abnormalities in process control systems.
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