JPH0638204B2 - Process display - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a process display device for displaying output states of control elements of a multiplexed process control system.

[Technical Background of the Invention and Problems Thereof] A process control system of a nuclear power plant is required to have extremely high reliability and safety due to its properties. For this reason, the detection unit, the amplification unit, and the operation unit of the process control system (which are called control elements in the present invention) are often multiplexed.

On the other hand, even if the control elements are multiplexed, it is difficult to secure a mounting space for indicators such as indicators and lamps that display the output state of the control elements, or the operability of the operator is reduced. It is generally not multiplexed.

In order to display the output state of the multiplexed control elements on the display which is not multiplexed, the signal of any one of the control elements is fixedly applied to the display, or the output of a plurality of control personnel is output. There is a method of selecting signals by majority logic and adding them to the display.

FIG. 2 is a block diagram showing the configuration of a conventional process display device for displaying the output state of the tripled control element.
In FIG. 2, the control elements 1A, 1B, which are tripled,
Even if any of 1C becomes abnormal, there is no problem in control because the output signals of other control elements are used for control.
However, since it is necessary to recognize which control element is abnormal, each control element is provided with abnormality detection circuits 2A, 2B, 2C for detecting its own abnormality.

Here, in order to display the output states of the multiplexed control elements 1A, 1B, 1C, a display 3A is connected to the control element 1A, and the outputs of the control elements 1A, 1B, 1C are input respectively. Intermediate value selection circuit 4 for selecting the intermediate value
Is connected to the display device 3B.

With this configuration, the output state of the control element 1A is fixedly displayed by the display device 3A, while the normal output state is displayed on the display device 3B even if any one of the control elements fails. It can be said that it is a simple process display device whose output state can be grasped even with a special device for selecting the output of the multiplexed control elements.

However, in this conventional process display device, the display 3A is also displayed as it is for an abnormality of the control element 1A, and the display 3A is not displayed at all for a functional stop of the control element 1A. It was very confusing in that it displayed a different status than the output to the process.

The intermediate selection circuit 4 is generally incorporated in the same device as any of the control elements 1A, 1B, 1C. For example, the control element 1A, the abnormality detection circuit 2A, and the intermediate value selection circuit 4 serve as the device 8. When they are put together, there is a problem that the operation of the intermediate value selection circuit 4 becomes abnormal with respect to the power supply abnormality of the control element 1A, and a predetermined signal is not given to the display device 3B.

[Object of the Invention]

The present invention has been made to solve the above problems, and an object of the present invention is to provide a process display device capable of constantly supplying a signal corresponding to the output of a control element having a normal function to a display.

[Outline of Invention]

The process display device according to the present invention, based on the output signal of the abnormality detecting means for determining whether the functions of the multiplexed control elements are normal or abnormal, outputs the output signal of any one of the control elements having a normal function. In addition to the display, when the function of this control element becomes abnormal, a switching means for switching the output signal of another control element having a normal function and adding it to the display is provided.

Example of Invention

FIG. 1 is a circuit diagram partially showing the configuration of an embodiment of the present invention in blocks, in which the same reference numerals as those in FIG. 2 denote the same elements.

In FIG. 1, triplicate control elements 1A, 1
B and 1C are provided with abnormality detection circuits 2A, 2B, and 2C for determining whether the function is normal or abnormal, and these control elements 1
The A, 1B and 1C and the abnormality detection circuits 2A and 2B are connected to the switching circuit 5, respectively.

In this switching circuit 5, the relay 6 that is excited when the function of the control element 1A is determined to be normal by the abnormality detection circuit 2A, and the function of the control element 1B is determined to be normal by the abnormality detection circuit 2B. The normally open contact 6a of the relay 6 is connected between the control element 1A and the indicator 3, and the normally open contact 7a of the relay 7 is included between the control element 1B and the indicator 3. And normally closed contact 6 of relay 6
b is connected in series, and the normally closed contact 7b of the relay 7 is connected between the control element 1C and the mutual junction point of the normally open contact 7a and the normally closed contact 6b. The operation of this embodiment will be described below.

First, when the functions of the control elements 1A, 1B and 1C are determined to be normal by the abnormality detection circuits 2A, 2B and 2C, respectively, the control element 1 is controlled by a signal selection circuit (not shown).
The output signal of any one of A, 1B, and 1C is given to the process. Further, the relays 6 and 7 forming the switching circuit 5 are excited by the outputs of the abnormality detection circuits 2A and 2B, which are determined to have the normal functions of the control elements 1A and 1B, thereby closing the contacts 6a and 7a. , Contact 6b,
7b opens. Thus, in this state the control element 1A
Output signal is applied to the display 3.

Next, when the function of the control element 1A becomes abnormal, a signal selection circuit (not shown) gives an output signal of either the control element 1B or 1C to the process. On the other hand, when the abnormality detection circuit 2A determines that the control element 1A is abnormal, the relay 6 is demagnetized, the contact 6a is opened, and the contact 6b is closed. Thus, in this state, the output signal of the control element 1B is applied to the display 3.

Next, if the function of the control element 1B also becomes abnormal, the output signal of the control element 1C is given to the process by a signal selection circuit (not shown). At this time, since the abnormality detection circuit 2B determines that the control element 1B is abnormal, the relay 7 is also demagnetized, the contact 7a is opened, and the contact 7b is closed. Therefore, in this state, the output signal of the control element 1C changes to the display 3
Added to.

Here, among the control elements 1A, 1B, and 1C, those having normal functions output mutually the same signals, so that the display device 3
The output of the normal control element is applied to the display 3 by the switching circuit 5 even from the control element in which the signal applied to the control signal and the signal used to control the process are different.

By the way, although the switching circuit 5 does not include a relay responsive to the abnormality detection circuit 2C, the control elements 1A, 1B,
If the display priority is determined for 1C as described above, it is extremely probable that the control element 1C will fail while the output signal of the control element 1C is being applied to the display 3. Since there are few, the outputs of the control elements of normal function are always applied to the display 3.

Although the switching circuit using the relay has been described in the above embodiment, the same operation as described above can be performed even if the circuit is configured by using the transistor instead of the relay or the soft logic using the microcomputer. be able to.

In the above embodiment, the control elements 1A, 1B, 1C have the abnormality detection circuits 2A, 2B, 2C, respectively. However, instead of this, the functions of the control elements 1A, 1B, 1C are changed by using a microcomputer. Even if it is configured to collectively judge whether each is normal or abnormal, and the switching circuit performs the switching operation based on the output signal of this microcomputer, the same operation as described above is performed.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, based on the output signal of the abnormality detecting means, the output of the control element having a normal function is added to the display, and when the function of this control element becomes abnormal, the function is activated. Since the switching means for adding the signal of the other normal control element to the display is provided, the effect that the output of the control element having the normal function can be always added to the display is obtained.

In addition, as shown in the embodiment, the switching circuit can also be configured by a relay, so that it is possible to provide a device having a simple configuration and high reliability at low cost.

[Brief description of drawings]

FIG. 1 is a circuit diagram partially showing the configuration of an embodiment of the present invention in blocks, and FIG. 2 is a block diagram showing the configuration of a conventional process display device. 1A, 1B, 1C ... Control element, 2A, 2B, 2C ...
Abnormality detection circuit, 3, 3A, 3B ... indicator, 4 ... intermediate value selection circuit, 5 ... switching circuit, 6, 7 ... relay.

Claims (1)

[Claims] 1. A display for displaying an output state of a control element of a multiplexed process control system, and an abnormality detecting means for determining whether the function of the control element is normal or abnormal, respectively.
Based on the output signal of the abnormality detecting means, an output signal of any one of the control elements having a normal function is applied to the display device, and when the function of the control element becomes abnormal, another output signal having a normal function is displayed. A process display device, comprising: switching means for switching the output signal of the control element and applying it to the display.