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The usage and principle of pull rod displacement sensor

Date：2021-09-15 00:00

　　The pull rod type displacement sensor adopts a potentiometer type displacement sensor, which converts the mechanical displacement into a resistance or voltage output which is linear or arbitrary functional relationship with the potentiometer element. Both ordinary linear potentiometers and circular potentiometers can be used as linear displacement and angular displacement sensors, respectively. However, potentiometers designed to measure displacement require a definite relationship between displacement change and resistance change. The movable brush of the potentiometer type displacement sensor is connected with the object to be measured, and the displacement of the object causes the resistance change of the moving end of the potentiometer. The change in the resistance value reflects the magnitude of the displacement, and the increase or decrease in the resistance value indicates the direction of the displacement. Usually, the power supply voltage is applied to the potentiometer, and the resistance change is converted into a voltage output. The traditional pull-wire displacement sensor has a step-like output characteristic because its resistance changes in a step-by-step manner when the brush moves. If such a displacement sensor is used as a displacement feedback element in a servo system, an excessively large step voltage will cause the system to oscillate. Therefore, the resistance value of each turn should be minimized in the production of the potentiometer. At the same time, another major disadvantage of the potentiometer-type sensor is that it is easy to wear, poor resolution, low resistance, and poor high-frequency characteristics, resulting in a decrease in measurement accuracy.

　　Its advantages are: simple structure, large output signal, convenient use and low price.