JPS636434A - Automatic fault diagnosis device for material testing instrument - Google Patents

Abstract

PURPOSE:To enable a CPU to decide automatically whether or not a load cell, a load amplifier, and a counter circuit have a fault by connecting the load cell to a reference resistance element and inputting reference pulses to the counter circuit. CONSTITUTION:A material testing machine 1 grips a test-piece 6 with chucks 4 and 5 and applies a tensile load, and pulses of frequency proportional to the elongation of the test-piece 6 are inputted to a pulse counter 11, so that the number of the pulses is displayed on a display device 12. Further, the output of the load cell 3 is inputted to a load amplifier 13 and the extent of the load is displayed on a load indicator 14. The CPU 9, on the other hand, connects the load cell 3 to the reference resistance element 16 by a switch 15 before the start of a material test and compares a load reference signal from the load cell 3 with a specific indication value to decide whether or not there is a fault. Further, the CPU 9 inputs reference pulses from a reference pulse generator 17 to the counter circuit 11 and decides whether or not the counter circuit 11 is normal or not on the basis of the number of counted pulses.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic failure diagnosis device for diagnosing the presence or absence of a failure in a measuring wire device in a material testing device.

(Prior art) In order to determine whether or not this device is normal, a device that measures the elongation or load of a test piece in a material test inputs a reference signal into this meter aI11 device, and uses this reference signal to determine whether the device is normal or not. Diagnosis is made by checking a predetermined indicated value for.

Conventionally, this reference signal has been generated by, for example, making the bridge resistance of a load cell in a load measuring device variable using a manual changeover switch, outputting it from the load cell, giving this output to an indicating section, and comparing it with a predetermined indicated value by an operator. It was determined whether the measuring instrument was normal or not.

However, performing such manual operations to check reference values takes time in the test preparation process, and is particularly inefficient in automatic material testing.

(Problems to be Solved by the Invention) An object of the present invention is to provide an automatic failure diagnosis device that automatically determines whether there is a failure in a measuring instrument in a material testing device.

(Means for Solving the Problems) The automatic failure diagnosis device for a material testing device according to the present invention includes a material testing device, a load cell that detects the load applied to a test piece by the material testing device, and an output signal of the load cell. A load amplifier that amplifies the output of the load amplifier, a load instruction word that indicates the output of this load amplifier, a detector that detects the elongation when a load is applied to the test piece, and an elongation amplifier that amplifies the signal detected by this detector. , a pulse generator that generates a pulse with a frequency proportional to this output based on the output of this stretch amplifier, a counter circuit that counts the number of pulses generated by this pulse generator, and an output of this counter circuit. A material testing device comprising a switch, a reference resistance element connected to the load cell via the switch, and an output of the load amplifier and an output of the counter circuit are calculated and stored. , and a CPU that issues a command signal based on a failure diagnosis rifI same-start signal issued from the outside, a reference pulse generator that generates a reference pulse based on the command signal of this CPU, the pulse generator, and the It is provided between the pulse generator and the counter circuit, and normally connects the pulse generator and the counter circuit, and switches only when receiving the C and PtJ command signals to connect the reference pulse generator and the counter circuit. The CPU further includes the following functions a to d.

a) Based on the failure diagnosis start signal, a command signal is issued to the switch to connect the base Fp=resistance element and the load cell, thereby causing the load cell to output a load reference signal.

b) Diagnosing whether or not there is a failure in the load cell and the load amplifier based on the load reference signal amplified by the load amplifier.

C) Diagnosing whether or not there is a failure in the counter circuit based on the reference pulse generated by the reference pulse generator.

d) If there is a failure, a failure signal is output; if there is no failure, the switch and the changeover switch are returned to their original positions, and the counter circuit is reset.

(Function) In the present invention, a CPU (central processing unit) issues a command signal to a switch and the changeover switch based on a failure diagnosis start signal issued from the outside, causes the switch to switch, and causes the reference pulse generator to It also issues a command signal and generates a reference pulse.

The load cell generates a reference signal by being connected to a reference resistance element via a switch.

This reference signal is amplified by a weighted amplifier and the C
Input to PU. The CPU diagnoses whether or not there is a failure in the load cell and the load amplifier based on the reference signal amplified by the load amplifier.

On the other hand, a reference pulse generated by the reference pulse generator based on a command signal from the CPU is input to the counter circuit via the changeover switch. This counter circuit counts the number of the reference pulses and outputs the counted number to the CPU. The CPU diagnoses whether or not there is a failure in the counter circuit based on this number of pulses.

When the CPU determines that there is a failure, it generates a failure signal, and when it determines that there is no failure, it returns the switch and changeover switch to their original states, and resets the counter circuit.

(Example) The figure is a block diagram showing an embodiment of the present invention.

The material testing device includes upper and lower chucks 4 that grip the test piece 6.
, 5 and a mount 2, a load cell 3, a load amplifier 13, a load indicator 14, and a test piece 6.
a detector 7 that detects the elongation when a load is applied to the elongation amplifier 8; and a pulse generator 18 that generates a pulse with a frequency proportional to the magnitude of the output based on the output of the elongation amplifier 8. , a counter circuit 11, and a display 12 for displaying the output of the counter circuit 11.

The automatic failure diagnosis device for a material testing device according to this embodiment includes a switch 15 connected to a load cell 3, and a reference resistance element 1 connected to the load cell 3 via this switch 15.
6, a CPU 9, and a reference pulse generator 17 that generates a reference pulse based on a command signal generated by the CPU 9;
It is provided between the pulse generator 18 and the counter circuit 11, and normally the pulse generator 18 and the counter circuit 11 are connected, and the reference pulse generator 17 and the counter circuit 11 are switched only when a command signal from the CPU 9 is received. It is equipped with a changeover switch 10 for connecting the two.

In the material test R1, a test piece 6 is gripped by an upper chuck 4 mounted on a mount 2 via a load cell 3, and a lower chuck 5, which is driven by an actuator (not shown) and is positioned symmetrically to the upper chuck 4. A tensile load or the like is applied to the test piece 6.

The elongation of the test piece 6 detected by a detector 7 attached to the gauge distance of the test piece 6 is amplified by an elongation amplifier 8 and becomes an input to a pulse generator 18 .

Pulse generator 18 generates pulses with a frequency proportional to the magnitude of the output of stretch amplifier 8. This pulse is CP
The pulses are input to a counter circuit 11 via a changeover switch 10 that is switched based on a command signal from U9, and the number of pulses is counted. The number of pulses counted by this counter circuit 11 is displayed on the display 12 and
It is input to PU9.

On the other hand, the load output is determined by the load cell 3 with bridge resistance.
is converted into an electrical signal by This converted electric signal is amplified by the load amplifier 13, and the magnitude of the load is displayed on the load indicator 14 and input to the CPU 9, where it is calculated and stored together with the elongation data.

In addition, before starting the material test, the CPU 9 issues a command signal to the switch 15 based on the failure diagnosis start signal, connects the load cell 3 and the reference resistance element 16 that changes the bridge resistance of the load cell 3, and loads the load cell 3. Output the reference signal. This load reference signal is transmitted to the load amplifier 13
is amplified and input to the CPIJ 9 and load indicator 14.

The CPU 9 compares the input load reference signal with a predetermined instruction value, and if they are the same, determines that there is no failure in the load cell 3 and load amplifier 13, and if they are not the same, determines that there is a failure. By comparing the value displayed by the load indicator 14 with a predetermined instruction value, it is also possible to determine whether or not the load indicator 14 is malfunctioning.

Furthermore, the CPU 9 also issues a command signal to the reference pulse generator 17 and the changeover switch 10, causes the changeover switch 10 to connect the counter circuit 11 and the reference pulse generator 17, and causes the reference pulse generator 17 to generate a reference pulse. let This reference pulse is input to a counter circuit 11 via a changeover switch 10 and the number of pulses is counted. Based on the counted pulse number, the CPU 9 compares it with a predetermined value and determines that there is no failure in the counter circuit 17 if it is equal, and determines that there is a failure if it is not equal.

Then, when the CPU 9 determines that there is a failure in the measuring instrument, it outputs a failure signal, and when it determines that there is no failure, it resets the changeover switch 10 and the switch 15, and resets the counter circuit 11.

In addition, as another example of application, when used in a Charpy impact tester, the reference pulse signal of the hammer angle can be used with an angle indicator,
Alternatively, by inputting it into an energy indicator, it is possible to automatically determine whether there is a failure in the measuring equipment.

(Effects of the Invention) According to the present invention, it is possible to input a reference signal to a measurement device in a material testing device, and automatically determine whether or not there is a failure in this measurement device based on the output signal. Material test preparation can be done efficiently.

[Brief explanation of drawings]

The figure is a block diagram showing an embodiment of automatic failure diagnosis equipment for a material testing device according to the present invention. DESCRIPTION OF SYMBOLS 1... Material test case, 2... Frame, 3... Load cell, 4.5... Chuck, 6... Test piece, 7...
Detector, 8... Extension amplifier, 9... CP (J, 10
... Selector switch, 11... Counter circuit, 12.
...Display device, 13...Load amplifier, 14...Load indicator, 15...Switch, 16...Reference resistance element,
17... Reference pulse generator, 18... Pulse generator.

Claims (1)

[Claims] A material testing machine, a load cell that detects the load applied to a test piece by the material testing machine, a load amplifier that amplifies the output signal of the load cell, and a load instruction that indicates the output of the load amplifier. a detector that detects the elongation when a load is applied to the test specimen, an elongation amplifier that amplifies the signal detected by the detector, and an elongation amplifier that is proportional to the output based on the output of the elongation amplifier. In a material testing device, the material testing device includes a pulse generator that generates pulses at a frequency of , a switch, a reference resistance element connected to the load cell via the switch, the output of the load amplifier and the output of the counter circuit are calculated and stored, and based on a failure diagnosis start signal issued from the outside. A CPU that issues a command signal, a reference pulse generator that generates a reference pulse based on the command signal of the CPU, and a reference pulse generator that is provided between the pulse generator and the counter circuit,
Usually, the pulse generator and the counter circuit are connected to each other, and the CPU further includes a changeover switch that is switched to connect the reference pulse generator and the counter circuit only when receiving a command signal from the CPU. , the following a to d
An automatic failure diagnosis device for material testing equipment characterized by having the following functions. a) Based on the failure diagnosis start signal, a command signal is issued to the switch to connect the reference resistance element and the load cell, thereby causing the load cell to output a load reference signal. b) Diagnosing whether or not there is a failure in the load cell and the load amplifier based on the load reference signal amplified by the load amplifier. c) Diagnosing whether or not there is a failure in the counter circuit based on the reference pulse generated by the reference pulse generator. d) If there is a failure, a failure signal is output, and if there is no failure, the switch and the changeover switch are returned to their original positions, and the counter circuit is reset.