Bi-Directional, Dual Channel, Hall Effect Speed Sensors

AI-Tek bi-directional, zero velocity sensors are self-calibrating
to the specific customer application and provide two independent
frequency outputs and a direction signal output to indicate change
in direction of the sensed, ferrous target. The bi-directional sensor
can also be referred to as a dual channel sensor since it utilizes two
Hall effect sensing elements, physically offset from each other.
Each element generates a single channel of target information,
identical in frequency and polarity, but offset in the time domain
(phase shifted). Special circuits inside the sensor are designed to
calibrate each channel to its application target, then analyze these
two channels of information for a phase lead / lag condition. The
direction output will then provide a logic 1 level for clockwise or a
logic 0 level for counterclockwise rotation, assuming proper sensor
orientation.