General information about Encoders:
Encoders are employed to convert the rotary movement into electrical signals and to obtain position, speed & direction measurements. Our incremental encoders are designed with an optical electronic circuit. With optical encoders, an engraved disc made of metal or glass associated with a mask interrupts an infrared beam emitted by a transmitting gallium arsenide diode. The number of pulses produced determines the system’s resolution, i.e. the number of increments per rotation. Every time the infrared beam is interrupted, this is registered by a receiver and then processed electronically. The result is a square wave output signal.
Two shifted photosensitive diode arrays deliver squared signals (A and B) in quadrature. The phase shift (90° electric) of signals A and B makes possible to determine the direction of rotation. In one direction, during the going up (mounting front) of the signal A, the signal B is equal to 1. In the other direction, during the going up (mounting front) of the signal A, the signal B is equal to 0.
The Z or ZERO signal comprises only one transparent window delivering one signal (per) turn. This signal is synchronized with signals A and B. This zero signal determines a position of reference and allows reinitializing the system at each turn. The electronic treatment delivers signals complementary to A, B and Z and makes it possible to remove electric noises by using a differential transmission of the signals.
