SU1442862A1 - Device for measuring maximum load in strength tests - Google Patents

Abstract

The invention relates to a test apparatus for controlling the strength properties of materials and improves the measurement reliability while simplifying the design of the device. The output signal from the sensor 9 force opens the key 2, through which from the generator 1 pulses to the counter 3 receives a pulse and increases the number recorded in it by one. This number is converted by the digital-to-analog converter 1 of the DAC to the voltage, which is subtracted from the voltage from the force sensor 9, while the key 2 is closed. As the force increases, the voltage at the output of sensor 9 grows and, if the voltage at the output of the DAC 1 1 is exceeded, it reopens the key 2. The process repeats. The number recorded in counter 3 is proportional to the maximum force value. 1 il.

Description

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The invention relates to a testing technique and can be used to control the strength properties of materials.

The purpose of the invention is to simplify the design and increase the reliability of the measurement by reducing the number of electronic components in the device,

The drawing shows the block diagram of the proposed device.

The device contains a key generator 2 connected in series 1, a pulse 2, a counter 3 and a digital indicator 4j a series-connected resistor 5, a diode 6, a threshold element 7 and a power-booster control unit 8, a force sensor 9 connected to the eTO output amplifier 10 and a digital-to-analog converter (IDL ) 11. The output of the counter 3 through the DAC 11 is connected to the input of the amplifier 10, the output of which is connected to the control input of the switch 2, the input of the amplifier 10 is also connected to the resistor 5, and the output to the diode 6,

The device works as follows.

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The energizer (not shown) of the testing machine is sensed: by force sensor 9, the transient electrical signal from sensor 9 is fed to amplifier 10, which generates an opening signal to control input of key 2. Through the last pulse from pulse generator 1 enters counter 3 , causing an increase in the number in it by one. The number in the counter 3 is highlighted on the digital indicator 4 and is converted to a voltage, ШШ 1 1. An increase in the number in the counter 3 per unit causes an increment in the voltage at the output of the DAC 11 by a step corresponding to the analog equivalent of a unit of the lower order code. This voltage is applied to the input of amplifier 10, where it is subtracted from the voltage supplied from force sensor 9.

The polarity of the total voltage at the input of the amplifier 10 becomes such that at its output a signal appears that closes key 2. As the force increases, the voltage at the output of sensor 9 innova beats the voltage from the output of the DAC M, which causes a polarity change input voltage

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the amplifier 10 and the appearance at its output of a signal opening the key 2, through which the pulse passes again to the counter 3. Thus, as the force grows, the sample at the input of the counter 3 receives another pulse and the number in the counter 3 corresponds to the current value of the accruing force. While there is an increase in the force, the mismatch at the input of the amplifier 10 does not exceed the magnitude of one step of the voltage of the DAC II. When the sample begins to fail, this mismatch increases, as the voltage from the output of the DAC 11 remains unchanged, and the voltage from the output of sensor 9 decreases, while the polarity of the signal is such that the key 2 is closed.

When the voltage at the output of the amplifier 10 reaches the threshold of the threshold element 7, the latter generates a command of the block 8 to turn off the power driver.

Diode 6 and resistor 5 feedback the amplifier 10, and diode 6 changes its gain depending on the polarity of the signal.

Claims (1)

Invention Formula A device for measuring the maximum load during the strength tests, which contains a force sensor connected to its input by a load meter and a sample breakdown signal generator, characterized in that, in order to simplify the design and increase measurement reliability, the load meter is designed as an amplifier, digital-analog converter and series-connected pulse generator, a key, a counter and a digital indicator; the output of the counter is connected via an analog-to-digital converter to the amplifier input, Exit is connected to the control input of a key signal generator fracture is formed as a series-connected resistor, diode, the threshold element and the energizer control unit, the input amplifier is connected to the resistor, and an output - with a diode.