Electronic measuring instruments electronic universal testing machine works

Electronic tensile testing machine is a modern electronic technology and mechanical transmission technology combined with the product, and give full play to their strengths and is composed of large sophisticated testing equipment, can be of various materials for tensile, compression, bending and so on a number of performance test, and has wide measurement range, high precision, fast response etc.. Reliable work, high efficiency, and can be carried out for test data real time displaying, printing.

Electronic tensile testing machine is composed of measuring system, drive system, control system, and computer structure.

A measurement system.

1 force measurement

With the force measuring sensor, amplifier and a data processing system to realize the measurement, the most commonly used measuring force sensor is a strain gauge sensor.

The strain gauge sensor, is by the strain, elastic element and some accessories ( compensation element, protective cover, a connector socket, loading component ), the ability to turn certain mechanical quantity into power output device.

Strain type pressure sensor and pull, domestic variety, main cylinder force sensor, spoke type force sensor, S double pass sensor, cross beam type sensor type.

From the mechanics of materials that, under the assumption of small deformation, an elastic element a little strain epsilon and the elastic element is proportional to the force, and the elastic deformation is directly proportional to. To type S sensor as an example, when the sensor is subjected to tension the role of P, due to the elastic element is adhered on the surface of a strain gauge, because the elastic element strain and external force is directly proportional to the size of the P, therefore the strain gauge access measurement circuit, the output voltage can be measured by measuring the magnitude of force, thereby.

For the sensor, generally using differential full bridge measurement, is the pasted strain plate bridge, R1, R2, R3, R4, the actual resistance equal 4 ( or 8) strain, that is R1 = R2 = R3 = R4, when the sensor is subjected to external force ( tensile or compressive ) role, sensor elastic element producing strain and the resistance value is changed, the change value of delta R1, Delta R2, Delta R3, Delta R4, the results of the original balance bridge, now is out of balance, bridge road has a voltage output, a delta E

The delta E = [R1R2 / ( R1+R2 ) 2] R1 / R1 - R2 / R2 + R3 / R3 - R4 / R4 ) U type U is outside the power supply bridge voltage further cylinder of

Delta E = [R2 / 4R2] (R1 / R - R2 / R + R3 / R - R4 / R ) U

The delta Ri / Ri = K - I on type

There are E = [UK / 4] ( E 1 - E 2 + e 3 - E 4)

In simple terms, the force caused by P sensor strain sheet deformation, leading to the bridge imbalance, which causes the output voltage of the sensor changes, we do this by measuring the variation of the output voltage can know the force size.

In general, the sensor output signal is very weak, usually only a few mV, if we directly to the signal to be measured, is very difficult, and can not meet the requirements of high precision measurement. Therefore must through the amplifier the weak signal amplification, the signal after amplification voltage up to 10V, the signal to an analog signal, the analog signal through the multiplex switch and A / D conversion chip into a digital signal, and then data processing, thus, force measurements to come to an end.

2 deformation measurement

Through the deformation measuring device to measure, it is used to measure the specimen at the test generated in the process of deformation.

The device has two chuck, after a series of transmission mechanism and arranged in the measuring device at the top of the photoelectric encoder together, when the distance between the two chuck change, drives the photoelectric encoder shaft rotates, photoelectric encoder will have a pulse signal output. Then the MCU to signal processing, we can draw the specimen deformation.

The 3 cross beam displacement measurement

The principle is the same as deformation measurement is roughly the same, by measuring the output of the photoelectric encoder pulses to obtain the amount of displacement of the beam.

The two driving systems.

Is mainly used for testing machine of movable beam, its working principle is by servo control system of motor, motor through the deceleration box and a series of transmission mechanism drives the screw rod to rotate, so as to achieve the purpose of controlling the moving beam. By changing the rotating speed of the motor, can change the speed of the beam.

Three. Control system

As the name suggests, is to control the testing machine operation system, the people through the console can control test machine operation, through the display screen can be informed of the status of testing machine and the testing parameters, if the machine is equipped with a computer, also can realize the functions by computer and data processing analysis, the test results of print. Testing machine with computer communication between generally use RS232 serial communication mode, it is through the computer behind the serial port (COM) communication, the technology is relatively mature, reliable, easy to use.

Computer four.

Used for collecting and analyzing the data, enter the test interface, the computer will continue to collect all kinds of test data, real-time to draw the test curve, automatically extracts various test parameters and output statements.

Copyright @ 2011-2013 Beijing public Sheng industry technology company with limited liability