Capacitive proximity switches consist of an RC-oscillator with a special multi-part sensing electrode. The electrode and the oscillator circuit have a tube connected with earth potential for lateral shielding. This enables flush mounting of the sensor in metal, since the electrical field is only present in front of the sensing electrode. This field is the active zone of the sensor.
When the conductive material is removed from the active zone, the oscillator is undamped and the oscillation amplitude decreases. The amplifier of the oscillator voltage and the sensitivity of the sensor can be altered by the built-in potentiometer.
The middle electrode together with the built-in re-coupling gives very effective compensation under conditions of humidity, dust or icing. Special circuitry automatically compensates for these influences. The preset sensing distance remains nearly constant. The electrode design, along with the compensating circuitry of capacitive sensors, is a unique design, and provides performance advantages far superior to other capacitive sensors.
The capacitive switches may be used to limit the level in tanks and containers. The contents may be fluids, pulverized or granulated materials such as PVC powder, dyes, flour, sugar, powdered milk etc. Further applications are as end and limit switches for checking and regulating machinery setting, (even if the materials are non-metallic as in conveyor belt positioning and material stacking); checking drive belts and paper reels for sag and tear. Additionally they may be used as detectors for counting metal and non-metal components.
Compared to a surface of water
|Square steel plate (100x100x1)||20||10||15||10|
|Round Steel Plate (30 X1)||11||6||4||2|
|Lupulin granulate 1800H||8||3||2.5||Head approx. 2mm immersed|
|Hostalen GC 8960H||8.2||1.5||2||Head approx. 1mm immersed|
|Hostyren||8.2||3||3||Head approx. 1mm immersed|
|BM scrap material (Z)||6.7||1.4||1||Head surrounded|
|Hostalen GC coarse powder||8||2||1.5||Head approx. 3mm immersed|