Inductive linear position sensors and switches are non-contact devices that determine an object’s linear or angular coordinates with respect to a reference point. Displacement is measured when the object moves from one position to another at a specified distance or angle. The output signal represents the object’s distance from the reference point. Output types include analog current levels, analog voltages, modulated analog outputs, and digital signals. Analog current levels such as 4 – 20 mA are suitable for sending signals over long distances. Analog voltages are simple, usually linear functions. Modulated analog outputs such as sine wave, pulse wave, amplitude modulation (AM), and frequency modulation (FM) signals are encoded, but still analog in nature. Several types of digital outputs are available. RS232, RS422, and RS485 are common serial, digital protocols. Popular parallel protocols include the general-purpose interface bus (GPIB), a standard which is also known as IEEE 488. Other digital outputs for inductive linear position sensors and switches include transistor-transistor logic (TTL) signals.

