Magnetic speed pickups are typically installed to measure the speed of a turbine. The output of these probes is a sine wave whose amplitude varies with the speed of the turbine shaft. This signal can be difficult to read using digital counter modules for the following reasons:
The two channel speed input module has been designed to produce a square wave output signal of constant amplitude regardless of input signal. The input filtering reduces noise interference with an option of phase lock loop (PLL) circuit to ignore high-frequency interference.