Precautions and application fields of capacitive sensors

Application fields of capacitive sensors

Capacitive sensors can be used to measure linear displacement, angular displacement, and vibration amplitude (up to 0.05 μ M), especially suitable for measuring mechanical quantities such as high-frequency vibration amplitude, precision shafting rotation accuracy, acceleration, etc. It can also be used to measure differential pressure, liquid level, material level, moisture content in grain, coating of non-metallic materials, oil film thickness, humidity, density, thickness of measuring point media, etc. It is often used as a position signal generator in automatic detection and control systems.

When measuring metal surface conditions, distance dimensions, and vibration amplitude, a single electrode variable electrode distance type capacitive sensor is often used. At this time, the measured object is one electrode of the capacitor, and the other electrode is inside the sensor. Aerospace, automotive manufacturing, petrochemical, brick burning, ceramics, surface treatment, atmospheric environment, environmental laboratory boxes, food, beverage, high-tech, heating, industry, metallurgy, meteorology, metrology, military, pharmaceutical, paper and other industries are all useful.

Precautions for using capacitive sensors

1. Capacitive sensor theory can detect any object. When detecting an object with a high dielectric constant, the detection distance is greatly shortened, and even increasing sensitivity will not be effective.

2. When using inductive loads (such as lamps, motors, etc.), large transient impulse currents may degrade or damage the AC two-wire capacitive proximity switch. In this case, an intermediate relay should be added as a transfer load.

3. The static leakage current of the DC two-wire proximity switch is 0.5~1mA. In some situations where the leakage current of the proximity switch is large, the DC three-wire proximity switch should be used to improve its anti-interference performance.

4. Capacitive proximity switches cannot be used in DC magnetic field environments above 0.02t, otherwise they may malfunction.

5. Due to the significant impact of moisture, dust, and other factors, capacitive sensors should be regularly maintained, including detecting changes in the installation position of objects and proximity switches, poor contact between wiring and connection parts, and dust adhesion.

6. Avoid using capacitive proximity switches in chemical solvents, especially in strong acid and alkali environments.

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