JPS60236017A - Sensor provided with self-diagnosing function - Google Patents

Abstract

PURPOSE:To make self-diagnosis with a simple device by providing a discriminator which selects the value having the smaller difference with the memorized previous measuring values when the difference between the measuring values determined by a pair of elements from a part to be measured exceeds a prescribed value. CONSTITUTION:A pair of data are determined by a pair of the measuring elements 31, 32 from the part to be measured. A difference between a pair of the data is determined by a comparator 33 and a signal indicating that either is defective is fed to the defect discriminator 34 when said difference is larger than the preliminarily set certain value. The discriminator 34 compares the previous data stored in a memory 35 and the data of this time with respect to the same measuring element, discriminates the system of the element having the larger difference as a defect and adopts the data having the smaller difference as normal data. The normal data is fed through a line L to an output part 41. The self- diagnosis is thus made with the simple device and the defective data are eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sensor with a self-diagnosis function that is particularly suitable for controlling and monitoring land-based power generation plants.

Conventionally, sensors used for controlling and monitoring various types of equipment on ships and on land have generally been multiplexed to increase reliability.

FIG. 1 shows an example of a duplex sensor, in which sensor 11,
12 measurement results are led to a comparator 14 in the control/monitoring panel 13. The comparator 14 compares the difference between the measurement results of the sensors 11 and 12 with an allowable deviation value. If either one of the sensors 11, 12 is out of order, the difference between the measurement results of the sensors 11, 12 exceeds the allowable deviation value. Therefore, when the comparator 14 detects this state, an alarm can be issued. Then, by manually switching the selector switch 15 to the normal sensor side in response to the alarm from the comparator 4, a normal measured value can be sent to the output section 16.

However, in the duplex sensor shown in FIG. 1, even if the comparator 14 issues an alarm, the sensor 1 is not activated.

There was a drawback that it was difficult to determine which of the 12 sensors was at fault. In addition, a comparator 14, a changeover switch 1
5 had to be set up within 1 Jl 13 for control and monitoring.

A triple sensor (20UT OF 3) shown in FIG. 2 is known as a sensor that overcomes the drawbacks of the dual sensor shown in FIG. 1. In the triplex sensor shown in FIG. 2, the measurement results of the sensors 21 to 23 are led to a comparator 25 in the control/monitoring panel 24. The comparator 25 compares the difference between the measurement results of the sensors 2 to 23 with the allowable deviation value. 25 comparators,
Even if any one of the sensors 2 to 23 is out of order, a normal sensor can be determined if the difference between the measurement results of the remaining two sensors is within the allowable deviation value.

Therefore, the comparators 25 can always send the measurement results of the normal sensors to the output section 26.

However, the triple sensor shown in FIG. 2 requires three sensors, which has the disadvantage of being expensive and requiring a lot of effort in terms of equipment. Also, like the duplex sensor, the comparator 25
had to be installed in the control/monitoring panel 24.

This invention was made in view of the above circumstances, and its purpose is to detect abnormalities by comparing a pair of measuring elements that extract electrical signals from a measurement target and the difference in output between the pair of measuring elements and a predetermined value. a comparator that stores and records the outputs of the pair of measuring elements; An extremely simple configuration can be achieved by including a determination device that compares the previous outputs of the pair of measurement elements and determines the output of the one with less lead conversion among the pair of measurement elements as the sensor output. Therefore, it is an object of the present invention to provide a sensor with a self-diagnosis function that can perform 20UT OF 3 functions (detection of defective sensor and function of automatically selecting a signal from a normal sensor as a sensor output).

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows the self-diagnosis function of the present invention, which incorporates measuring elements 31 and 32 for extracting electrical signals from the object to be measured, a comparator 33, a defective determiner 34, and a memory 35. sensor 30
The defective determination device 34 (inner) is connected to the control/monitoring IJJHo (output unit 4)) by a sensor output transmission line.

Next, the operation of the configuration shown in FIG. 1 will be explained. Measuring element 31.
The output signal (measurement result, measured value) from 32 is sent to comparator 3
I am guided by 3. The comparator 33 compares the level difference between the signals from the measurement elements 31 and 32 with a preset allowable deviation value. When the comparator 33 detects that the level difference exceeds the allowable deviation value, it outputs an abnormality detection signal (indicating that either one of the measuring elements 31 or 32 is malfunctioning) to the defect determiner 34. do.

The defect determiner 34 scans the output signals from the measurement elements 31 and 32, and stores the corresponding scan data in a predetermined area of the memory 35 each time the signal is scanned. The scan data (from the measurement elements 31, 32) in the memory 35 is therefore updated for each signal scan. Upon receiving the abnormality detection signal from the comparator 33, the defect determiner 34 calculates the difference between the latest scan data from the measurement elements 31 and 32 and the previous scan data stored in the memory 35 from the same measurement element. The data are compared and the difference between them (that is, the amount of data change) is compared. Then, the defective determiner 34 determines that the measuring element exhibiting a rapid data amount fluctuation among the measuring elements 31 and 32 is defective (faulty), and converts the scan data of the measuring element with a smaller amount of data change into a normal one. Select as data (measured value). In the case of the sensor 30, this selection data can also be used by the defect determination device 34 to send an alarm signal indicating the occurrence of a failure of the measuring element to the control/monitoring 914o together with the selection data (normal measurement value). Note that if both the measurement elements 31 and 32 are normal, it does not matter which data is sent.

As described in detail above, according to the present invention, the 2OUTOF3 function, which was conventionally achieved with three sensors and a signal processing section, can be achieved by integrating a pair of measurement elements and a signal processing section into a single highly reliable system. This can be realized using multiple sensors. Moreover, the sensor output transmission gauze from the sensor to the control/monitoring panel is different from the conventional 3.
The number of sensors can be reduced from one to one, and together with the compactness of the sensor itself, the entire system can be simplified and the price can be reduced.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are block diagrams showing a conventional example, and FIG. 3 is a diagram showing a Kirinari skin splitting/monitoring system to which the sensor with self-diagnosis function of the present invention is applied. 30...Sensor (sensor with self-diagnosis function), 31.3
2...Measuring element, 33...Comparator, 34...Failure determiner, 35...Memory. Patent attorney Suzue Takehiko

Claims (1)

[Claims] A pair of measuring elements that take out an electrical signal from a measurement target, a comparator that compares the difference in the output of the pair of measuring elements with a predetermined value and detects an abnormality, and a comparator that stores the output of the pair of measuring elements. , according to the memory to be updated and the abnormality detection of the comparator, compare the latest output of the pair of measuring elements with the previous output of the pair of measuring elements stored in the memory, and
A sensor with a self-diagnosis function, characterized in that it is equipped with a determining device that uses the output of a pair of measuring elements having a smaller output change as the sensor output.