The KD-2440 system operates on a traditional Colpitts oscillator circuit where the sensor acts as the resonating coil for the oscillator. The proximity of the target to the sensor face pulls the oscillator, changing its frequency and amplitude of modulation, and controlling a variable gain oscillator section within the electronic circuit.

The signal is half-wave rectified and filtered to obtain an analog voltage proportional to the target position or displacement. The analog voltage output can be varied by adjustment of the gain. The input power is diode protected and regulated to provide a clean low-noise signal. The output is short-circuit current protected.

The KD-2440 may be used in a variety of applications using target materials such as ferrous or stainless steel or aluminum. Good sensitivity to small diameter targets lends itself to applications such as gear teeth counting, RPM measurement, or thread detection (see application note Detection of Magnetic Threads Using the KD-2440). The opto-isolated switched output makes the KD-2440 ideal for interfacing to PLC inputs, counters, timers or alarm circuits.

The KD-2440 system consists of three sub-assemblies: the sensor, with integral cable, a power and output cable, and the signal conditioning or electronics module. The KD-2440 electronics use a standard DB-9 connector to bring +12 Vdc to +24 Vdc into the electronics and provide outputs for the variable voltage and switch functions. Kaman offers either the P-3410 or P-3450 power supplies. The system comes standard with one of two production sensor configurations – the 9C or the 5CM. Both of these sensors are rated to moderate temperatures and can withstand temperatures to 400° F (205° C).