JPS588301A - Multiplex controller - Google Patents

Abstract

PURPOSE:To minimize the disturbance to the entire plant even at a failure of a control unit, by providing each one set to a plurality of controlled systems and controlling two other controlled system. CONSTITUTION:Controlled systems V1-V4 are individually controlled via 2 out of 3 logical circuits TOUTU1-TOUTU4 with control programs P1-P4 of control units CU1-CU4 provided at each controlled system based on an input signal from input circuits IN1-IN4. For example, the output of the P1 of the CU1 is inputted to the TOTU1 together with the output of each P1 of the CU3 and CU4 and outputted to the V1 via the logical judgement at the TOTU1. If the CU1 is failed, when the control output from the CU1 is an analog signal, the output of the P1 of the CU1 in the TOTU1 is separated, an average value between the CU3 and CU4 is calculated and outputted to the V1. When the control output of the CU1 is a digital signal, the logical product of both the control outputs of the CU3 and CU4 is outputted to the V1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplexed control device that controls a large number of control objects simultaneously and in parallel, such as turbine trip control, for example.

Conventionally, in protection control devices such as turbine trip control in thermal power plants, hardware is triplexed and signals are output from two of the three devices to prevent mistrips due to hardware malfunctions or malfunctions. A highly reliable system configuration based on so-called 20UT OF 3 logic, which operates when

FIG. 1 is a diagram showing an example of a conventional triplex system. In this figure, CU, to CU3 are output circuits of each control unit;

~2N4 indicate input circuits, respectively. This operation will be explained below. Control program P for four controlled objects V, ~V4, ~i) 4'f: each control unit) CU, ~
It is built into the CU and executes control calculations based on the input signals IN, to IN4. The calculation results are sent to the output circuits OU, ~OU
3' to TOTU. At TOTU, 3
If two or more of the base control units are normal, the average value of the normal control unit output is fully output, and if two or more are abnormal, the control signal to the control pair is completely cut off or held. . In this example, one control unit executes control of all control targets, so if there are many control targets, the computer load on the control unit increases, and the responsiveness of the heel control decreases. Of the three control units,
There is a drawback that the output fluctuation when one unit breaks down is applied to all controlled objects at the same time.

FIG. 2 shows an example in which the control unit and 2 OUT OF 3 logic circuits are distributed in order to eliminate the drawbacks of the conventional example described above. This configuration improves responsiveness and reduces disturbance in the event of control unit failure, but since three control units are required for each control target, it is costly, especially when there are many control targets. There is a drawback that the amount is enormous.

It is an object of the present invention to eliminate the drawbacks of the prior art, to reduce the disturbance given to the entire platform in the event of a control failure, without impairing the responsiveness of control, and to reduce the disturbance caused to the entire platform when a control failure occurs, even if two control units fail. It is an object of the present invention to provide a multiplex control device that can reduce the number of controlled objects that become uncontrollable even if such a problem occurs, and reduce the adverse effect on a side-collapsed object.

The first feature of the present invention is that one control unit is provided for each of a plurality of control objects, and each control unit is configured to control two other sets of control objects in addition to the control object. be. The second feature is that, based on the control blades from two control units other than the control unit for each controlled object, during normal times, the average value of the normal control unit output is fully output, In case of abnormality, 20UT
The OF3 logic provides all the means to control the controlled object.

FIG. 3 shows an embodiment of the present invention. Control units CU, ~CU provided for each controlled object based on human input signals from input circuits IN, ~IN4, respectively, of controlled objects V1 to v4
, control programs P1 to P, output circuit OU+
~OU4.2 0UTOF 3 logic circuit ToTU1
~ToTU4 and are individually controlled via relay contacts R, Y, and f. For example, the output of the control program P1 of the control unit CU, CU3. It is input to TOTU1 together with the output of each P1 of CU, and after a logical judgment there, it is output to controlled object (2). control unit) CU,
When the control output from CU1 is an analog signal, when the control output from CU1 is an analog signal, the self-failure diagnosis circuit SD1 disconnects the output from the program P1 of the CU in TOTU1, and the other CUs.

The average value is calculated between the output of CU4 and the output of relay contact 1.
'(Output to the controlled object ■ via yt k.

If the control output from CUl is a digital signal, CU
3 and CU4 control output, the logical product of both is relay i point RY
1i to the controlled object V.

CU, feed CU3. When all of CU4 is normal, the control output to the controlled object is cul, CU if it is an analog signal.
3,, the output average value of program P1 of CU4 is,
In the case of digital signals, it is a logical product.

Next, when CU1 and CU3 fail, the internal 20UTOF of TOTUI and TOTU3 is activated by the signal from the self-failure diagnosis circuit SD, 5-D3.
3 logic, each grinding output is connected to the phosphorus contact Ry,
, Ry, is blocked. In addition, even if either of the two control units fails, the number of control objects that cannot be operated remains at two.

Although an example in which there are four controlled objects has been described here, the configuration and operation are similar to those described above even when there are many controlled objects.

According to the invention, it is possible to minimize disturbance to the entire plant even in the event of a control unit failure without impairing control responsiveness.
Even if two control units fail, only two controlled objects become uncontrollable, and a highly reliable and inexpensive control device can be constructed.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing the configuration of a conventional control device, respectively, and FIG. 3 is a block diagram showing an embodiment of the present invention. IN, ~■N4...Input circuit, CU, ~CU4...
Control unit, SD, ~SD4...Self failure diagnosis circuit, TOTU1~TOT U,...2 OUT
OF 3 logic circuit, OU1~OU,...output circuit, P
, ~P4...Control program, ■1~V4...Controlled object, Ry1~Ry,...Relay contact. Figure I INt INz IA/J IN+Vt V2
V3 Vt Figure 2Vt 7z V JFigure 3

Claims (1)

[Scope of Claims] 1. In a device that individually controls a plurality of control objects, a control unit capable of controlling three control objects is provided for each control object, and each control unit is provided with another control unit. A multiplex control device characterized in that the control devices are combined in a ring shape so as to control two control objects. 2. According to the description in claim 1, it is further provided that, based on all the control outputs from two control units other than the control unit for each controlled object, the average value of the normal outputs during normal times is calculated. A multiplex control device characterized in that it is provided with means for locking the control output to a controlled object using two-out obnoxious logic in the event of an abnormality.