A Magnetic Pickup consists of a permanent magnet, a pole-piece, and a sensing coil all encapsulated in a cylindrical case. An object of iron, steel, or other magnetic material, passing closely by its pole-piece causes distortion of the magnetic flux field passing through the sensing coil and pole-piece, which in turn generates a signal voltage. The magnitude of the signal voltage depends on the relative size of the magnetic target, its speed of approach, and how close it approaches. The polarity of the signal depends on whether the target is moving toward or away from the pole-piece.
Magnetic Pickups are most frequently used to sense passing teeth on a gear, sprocket, or timing belt wheel, to bolt-heads, key-ways, or other moving machine mounted targets. Typical targets and resulting signal wave forms are shown within the datasheet. Selecting a magnetic pickup is a matter of matching a pickup to a gear (or other target), to provide enough input signal to a tachometer, speed-switch, or other device for operation at the required minimum speed. The open-circuit output from a magnetic pickup is directly proportional to speed, and once the minimum operating speed conditions have been met, excess signal will always be available at higher speeds.

Self generating
No external power needed
Wide operating temperature range
Epoxy encapsulated
Mechanically rugged
Impervious to dirt, oil and water
No maintenance required
M12 connector (Model specific)
For use with speed switches, digital tachometers, frequency to D.C. converters

Magnetic Pickups are used primarily for tachometer and other speed related functions. They are not normally used for counting since loss of counts will occur at low speeds. Therefore, counters are not designed to accept outputs directly from conventional magnetic pickups. In special applications where counting occurs only at running speed or where low-speed count loss is acceptable, a Model ASTC can be used, or a different type of sensor can be used as a substitute.

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