TURCK, represented by Micromax , has announced the introduction of the new ac version noise immune capacitive sensors or "BCF" sensors.
These ac sensors incorporate the same unique filter principle as the dc versions, making them immune to most industrial noise.
This principle involves a fixed oscillator frequency combined with a rectifier filter providing superior noise immunity.
Turck's fixed oscillator allows the sensor to maintain a constant frequency regardless of sensitivity adjustment. This fixed frequency is high enough to ignore most of the "standard" noise levels seen on plant floors.
Electrical noise is mostly symmetrical which makes it easier to identify and separate from the sensor's input signal. The Turck rectifier filter is able to block this noise, allowing only the "useful" input signal, which is in phase with the oscillator frequency, to pass.
Sensors in general have a very difficult time in electrically noisy environments and capacitive sensors are no exception. Electrical noise can have adverse effects on sensing devices and cause them to operate improperly and unreliably.
The BCF capacitive sensors have been tested to a higher standard than required, exceeding most of the specifications listed by CE. These new BCF sensors are now available in 18mm and 30mm plastic barrel housings for dc and 30mm plastic housing for ac.