JPH01283081A - Double signal selecting device - Google Patents

Abstract

PURPOSE:To improve reliability by comparing signals from doubled detectors with each other and a set value to be controlled from a setter, and logically comparing and judging the troubles of detectors. CONSTITUTION:Two speed signals detected by two speed detectors 6a, 6b are supplied to a high value selector 8 in a selecting device 12. A switch unit 11 selects an output signal from the selector 8 at the time of normal state, and outputs a deviation from a set signal from a setter 9 to a speed controller 10. The signals from the detectors 6a, 6b and a set signal from the setter 9 are input to a logical comparing discriminator 13, a difference from the signals of the detectors 6a, 6b is obtained with the set signal as a reference, and the difference of the two speed signals is also detected. If it is judged that the deviation from the set signal is large and the deviation of the signals is large, a switching command to a normal side speed signal is generated to the unit 11 of the device 12.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) Regarding abnormality diagnosis of detection circuits including detectors of measurement and control equipment such as plants, especially when one of the duplex detection circuits fails, The present invention relates to a device for identifying and disconnecting an abnormality detection circuit.

(Prior Art) For example, a recirculation flow rate control system that controls the output of a boiling water reactor includes a variable frequency MG set 1 as shown in FIG.
Drive motor 2 driven by this, recirculation pump 3, scoop pipe operator 4 that operates the scoop pipe of the fluid coupling in variable frequency MG set 1, speed controller 5 and two speed detectors 6a, 6b. It is configured. The flow rate control of this recirculation flow rate control system is performed by changing the power frequency of the drive motor 2 of the recirculation pump 3 and changing the speed of the recirculation pump. The position of the scoop tube is adjusted, thereby changing the rotational speed of the generator and changing the output frequency. At this time, the rotational speed signal of the generator is determined by the speed control aII device 5, which is provided with two speed detectors 6a and 6b in order to obtain high reliability.
to communicate.

FIG. 3 is a diagram showing a conventional speed detector, in which two speed detectors 6a are arranged near the outer periphery of a gear 7 connected to a generator.
, 6b are duplicated, each signal is input to the high value selector 8 in the speed control device 5, the larger value is adopted, and the deviation signal from the setting value of the setting device 9 is used as the speed signal. It is input to the control circuit 10.

In addition, this duplexing device has been widely employed in the motor gear unit position detector in the control unit of a turbine-driven water supply pump, the scoop tube position detector of the scoop tube operating device 4, and the like.

(Problem to be Solved by the Invention) If one of the duplicated speed detectors 6a16b fails, the characteristics of the duplex speed detector 6a16b will change even if an abnormality is diagnosed, except in cases where the degree of failure is a clear phenomenon in which the signal becomes zero due to disconnection, etc. Due to deterioration, it is difficult to identify which one has failed, especially when a detector has failed and the output signal is higher than the normal value.
Nuclear reactors have the problem of being controlled to reduce their output, and as a countermeasure to this problem, it has been difficult to identify failures without installing complicated and expensive equipment.

SUMMARY OF THE INVENTION An object of the present invention is to provide a duplex signal @ selection device which adds a simple device to identify and select a detection circuit failure in a duplex device and disconnects the detection circuit.

(Means to be Solved by the Invention) Means for comparing signals from duplicated detection circuits with a set value to be controlled from a setting device to logically compare and determine failure of each detection circuit, and this means A selection means is provided for disconnecting the abnormality detection circuit from the measurement and control device when it is determined that the abnormality is abnormal.

(Function) Normally, the output of the high value selector that receives the signals from the two detection circuits is selected by a switch and supplied to the control circuit, but if one detection circuit fails and its output shows an abnormality, An abnormality is detected by comparing and calculating the deviation between this value and the other normal detection signal and setting value of the setting device, and the switch is switched to the other normal detection circuit, and the occurrence of an abnormality is notified to the detection circuit. do.

(Example) An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of the speed detection section of the recirculation flow rate control system.
a selection device 12 consisting of a high value selector 8 which inputs a generator rotational speed signal from and outputs the high value thereof, and a switch 11 which switches this output or the output signals of the two speed detectors 6a and 6b; The output signals of the two speed detectors 6a, 6b and the signal from the setting device 9 are input, and the deviation between the output signals of the two speed detectors 6a, 6b and the output of each of the two speed detectors 6a, 6b are determined. Based on the deviation between the signal and the setting signal of the setting device 9, the abnormal speed detection circuit is identified and the switch 11 of the selection device 12 is operated to the normal speed detection circuit side, and the occurrence of this abnormality and the abnormal speed detection circuit are notified. It is composed of a logical comparison and judgment device 13 that performs the following.

Next, the operation of the above configuration will be described. The two speed signals detected by the two speed detectors 6a and 6b are selected by the high value selector 8 in the selection device 12 and applied to the switch 11 together with the output thereof. During normal operation, the switch 11 selects the output signal from the high value selector 8 and outputs the deviation from the setting signal from the setting device 9 to the speed control circuit 10. In addition, the speed signals of the speed detectors 6a and 6b and the setting signal from the setting device 9 are input to the logical comparison and judgment device 13, and the logical comparison and judgment device 13 uses the setting signals as a reference to detect each speed detector 6a and 6b.
The difference between the speed signal and the speed signal is detected as well as the difference between the two speed signals. If the deviation from the set signal is large and the deviation between the speed signals is also large, it is determined that the speed detection circuit is abnormal and a command is sent to the switch 11 of the selection device 12 to switch to the normal speed signal. emanate.

As a result, the switch 11 changes the output signal of the high value selector 8 to
The speed signals of the speed detectors 5a and 5b are switched to the normal side, and the difference between the speed signals and the set value of the setting device 9 is output to the speed control circuit 10. Further, from this switching operation, it is reported that an abnormality has occurred in the detection circuit including the speed detector, and the detection circuit is identified and notified.

Therefore, even if the speed detection circuit fails, the nuclear reactor is not affected and can maintain normal operation without output fluctuation according to the correct generator rotational speed signal and the set value of the setting device 9.

[Effects of the Invention] According to the present invention, although the duplex circuit is the same as the conventional one, it is possible to constantly detect an abnormality in the detection circuit during operation, notify the same,
Since it is possible to automatically switch to a normal circuit, it has the effect of improving the operating efficiency and reliability of plants such as nuclear power plants as well as the measurement and control devices employed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a speed control detection section according to an embodiment of the present invention, FIG. 2 is a block diagram of a reactor recirculation flow rate control system, and FIG. 3 is a block diagram of a conventional speed control detection section. 6a, 6b...Speed detector 7...Gear 8...High value selector 9...
Setting device 10...Speed control circuit 11...Switching device 12...Selection device 13...Logical comparison and judgment device Agent Patent attorney Norifu Ogo Figure 1

Claims (1)

[Claims] In a measurement and control device in which a detection circuit including a detector is duplicated, a means is provided for comparing the signal of the duplicated detection circuit with a set value to be controlled to make a logical comparison judgment of a detection circuit failure, and a method for detecting an abnormality by this means. 1. A duplex signal selection device comprising a selection means for disconnecting an abnormality detection circuit from a measurement and control device when a determination is made.