Capacitive level sensors are suitable for industrial enterprises to measure and control the production process in the production process, mainly used as conductive and non-conductive media liquid level or powder granular solid level of long-distance continuous measurement and indication.
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The capacitive liquid level sensor is composed of a capacitive sensor and an electronic module circuit, which is based on a two-wire system of 4 ~ 20mA constant current output. After conversion, it can be output by three or four wires, and the output signal is formed into 1 ~ 5V, 0 ~ 5V, 0 ~ 10mA and other standard signals. A capacitive sensor consists of an insulated electrode and a cylindrical metal container containing a measuring medium. When the material level rises, because the dielectric constant of the non-conductive material is obviously less than the dielectric constant of the air, the capacitance changes with the change of the material height. The module circuit of the sensor is composed of reference source, pulse width modulation, conversion, constant flux, feedback and current limiting. The advantages of using the pulse width modulation principle are low frequency, RF interference to the surrounding elements, good stability, good linearity, no obvious temperature drift and so on.
