JPH0423002A - Process controller - Google Patents

Abstract

PURPOSE:To prevent the sudden change of an operation signal by detecting through an operation signal range detecting means whether the operation signal of an operation terminal is kept within a necessary range or not and inhibiting the acceptance of a switching request to an automatic operation as long as the operation signal is not kept within the necessary range in an automatic operation switching state. CONSTITUTION:A deviation signal DV between a process deviation signal PV and the set value SV is inputted, and a necessary operation is carried out at a PID control arithmetic part 1. The operation signal MV is set within a necessary range by a limiter means 2 and then outputted to an operation terminal of a plant. When a switching request is accepted to an automatic operation, an MV range check means 5 checks whether or not the signal MV of the operation terminal is kept within the rang set by the means 2. If not, an automatic operation switch control means 6 is prevented from switching an automatic/ manual changeover switch 4. Then the acceptance of the switching request is inhibited for the automatic operation. At the same time, this fact is shown and reported through a display means 7. Thus the sudden change of the signal MV is avoided and the safety is improved for a processor controller.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a process control device that inputs and controls process variables such as temperature and pressure.
The present invention relates to a process adjustment device that performs PID control calculation on a deviation signal between a process amount and a set value, and outputs the calculation result (operation signal) to an operation end such as a valve via a limiter means that limits upper and lower limit values.

<Prior Art> Conventionally, PID controllers used for process control have been equipped with a limiter means for suppressing the operation signal (MV> to a range between a certain upper limit IMH and a certain lower limit ML, and have been automatically adjusted. It is configured to prevent the operating signal at the time from being output exceeding the upper and lower limits, thereby maintaining the safety of the operation.

In addition, a manual adjustment means is provided in case the PIDililH11I calculation section fails, and the configuration is such that the operation signal can also be changed by manual operation.

Here, the manual operation signal from the manual adjustment means is transmitted from the operation end (
It is designed to output values that exceed the upper and lower limits of the limiter so that control such as starting up the plant can be performed.

<Problems to be Solved by the Invention> In the process controller constructed in this research, it is possible to avoid situations in which the value of the operation signal due to manual operation exceeds the range of the upper and lower limit values of the limiter in a manual operation state. When switching to the automatic operation state, the operation signal is eventually pulled back from the manual operation value up to that point to the upper limit value MH or the lower limit value ML.

For this reason, the operation signal MV output to the valve or the plant changes rapidly, causing a problem that the plant may be adversely affected.

The present invention has been made in view of the above points, and is designed to prevent switching to automatic driving if there is a risk that the operation signal MV will change suddenly when switching to automatic driving, thereby improving safety. The objective is to realize a process control device with high performance.

Means for Solving the Problems> The present invention for solving the above problems consists of performing control I calculation on the deviation signal between the process amount and the set value,
A process control device that outputs the calculation result to the operating end via a limiter means, wherein upon receiving a request for switching to automatic operation, the value of the operation signal output to the operating end is within the range of upper and lower limits of the limiter means. an operation signal range inspection means for inspecting whether or not the operation signal range is the same; and in the operation signal range inspection means, if the value of the operation signal is outside the range of the upper and lower limit values of the limiter means, the request for switching to automatic operation is rejected. At the same time, it is configured with a small number of automatic operation switching control means that notifies the user of this fact.

<Function> The operation signal range inspection means receives information regarding the upper and lower limit setting values ML and MH from the limiter means and the operation signal M to the operation end.
When the value of V is input and a request to switch to automatic operation is received, the operation signal MV currently output to the control terminal changes to M
It is checked whether L≦MV≦MH.

The automatic operation switching control means switches to automatic operation when the operation signal MV is within the range of upper and lower limit set values ML to MH of the limiter means.

This makes it possible to prevent sudden fluctuations in the operation signal when switching to automatic operation.

<Example> Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a configuration block diagram showing an embodiment of the present invention. In FIG. This limiter means inputs the calculation result of the control calculation section 1 and suppresses the operation signal MV within the range between the upper limit value MH and the lower limit value ML. Here, each of the upper limit value MH and lower limit value ML can be freely set according to the plant to be controlled.

3 is a manual adjustment means used when manually controlling the operating end, and 4 is an automatic/' for switching between automatic operation and manual operation.
The manual changeover switch selects the signal from the PIDiilJIll calculation unit 1 outputted via the limiter means 2 during automatic operation, and selects the signal from the manual adjustment means 3 during manual operation.

Reference numeral 5 denotes an operation signal range checking means for determining whether or not the value MV of the operation signal outputted to the operating end is within the upper and lower limit values of the limiter means 2 upon receiving a request for switching to automatic operation; rIM of the operation signal in the operation signal range inspection means 5
When V is outside the range of the upper and lower limits of the limiter Pi2, the automatic operation switching control means rejects the request for switching to automatic operation and notifies the display means 7 to that effect.

Note that the PID control unit 1 and each of the means 2 to 6 may be realized by a program installed in an M# station (computer) that controls the plant. C of the operator station serving as a machine interface chair
It may also be one that uses RT.

The operation of the apparatus configured in this way will be explained next.

FIG. 2 is a flowchart showing an example of the operation. Here, there is an operator station and a control station for plant control that operates according to instructions from the operator station, and these operations are shown.

First, before operating the plant, the operator presses the automatic operation button provided at the operator station to command automatic operation (STI>). When this button is pressed, the operation starts from the operator station to the control station. A state change request is sent (Sr1)
.

Upon receiving this request, the control station starts a program for changing the operating state. In the operation state change process, the command to change the operation state may be issued from within the control station, so first, it is determined whether the request is from the operator (Sr1). If it is determined that this is the case, read the operation signal MV output to the operation end and check whether the value is between the upper limit value MH and lower limit value ML set in the limiter means 2, that is, ML≦MV≦ Determine M H (Sr
4,5).

Here, if the operation signal MV is within the range of ML to MH, switching to automatic operation is enabled, the automatic manual changeover switch 4 is connected to the contact A@, and a request completion notification is sent to the display means 7. (Sr1°7), thereby entering the automatic operation state, and outputting the control output from the PID control calculating section 1 to the operating end via the limiter means 2 as an operating signal.

In step 5, if the operation signal MV is outside the range of ML to MH, the operation signal will suddenly change and it is dangerous to switch to automatic operation, and a notification that the request cannot be made is issued (Sr8). In this case, the automatic/manual changeover switch 4 is maintained in its original state and the automatic operation is not switched.

When the display means 7 receives a notification that the request is not possible, it displays a message to that effect, for example, "misoperation."

Note that when receiving a notification that the request has been completed, there is no display, or there is a display indicating that automatic operation has started.

The operator monitors these displays and, for example, if there is a display indicating "erroneous operation", the operator manually adjusts the operation signal M.
By performing an operation to bring the value of V within the range of ML to MH and then pressing the automatic operation button again, it is possible to switch to automatic operation without causing sudden fluctuations.

<Effects of the Invention> As explained in detail above, according to the present invention, when the operating state is switched to automatic operation, when the value of the operation signal exceeds the upper and lower set value range of the limiter means, That is, in the case where the operation signal suddenly changes due to switching and there is a danger, switching to automatic operation can be prevented, and a highly safe adjustment device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a configuration block diagram showing one embodiment of the present invention, and FIG.
The figure is a flowchart showing an example of the operation. 1...PID control all calculation unit, 2...Limiter means 3...Manual adjustment amniotic membrane 4...Automatic manual changeover switch 5...Manipulation signal (MV) range inspection means 6...Automatic operation switching Control means 7...display means

Claims (1)

[Claims of Claims] A process control device that performs control calculations on a deviation signal between a process amount and a set value, and outputs the calculation results to an operating end via a limiter means, which receives a request for switching to automatic operation, operating signal range testing means for testing whether the value of the operating signal output to the operating end is within the upper and lower limit values of the limiter means; 1. A process regulating device comprising: automatic operation switching control means that rejects the request for switching to automatic operation and notifies the request to that effect when the value is outside the range of the upper and lower limit values.