Incremental encoders rely on external electronics to interpret theposition based on the count of the events that occurred on that device.The outputs for incremental encoders can come in the form of a singlesquare wave(A), phased square waves(A and B) to determine direction ofrotation, or phased square waves and an index or one pulse per revolution(A, B, and Z). The concept of phasing square waves to determine rotationaldirection is often referred to as “quadrature”. The means of achieving an incremental signal are typically referred toas the encoder engines. The two primary encoder engine categories are optical and magnetic. In both engines, similarsensor alignment is performed to provide output compatibility.In the optical design, light is generated by an LED and detected by a chip‐level sensor. Between the two is a codedisc, typically made of glass, metal, or plastic. In an incremental encoder, the code disc is etched, coated, or punched(if metal) with a fine grating of similar lines around the circumference. In the magnetic design, there is a magneticwheel or disk, a magneto‐resistive sensor, and a conditioning circuit. The disk or wheel is magnetized with severalpoles. The sensor converts the sinusoidal change in magnetic field to an electrical signal as the disk or wheel rotates.That electrical signal is multiplied, divided, or interpolated by the conditioning circuit to produce the desirablesquare wave output.
Incremental encoders continue to lead in the area of speed feedback with no signs of slowing. Incremental encoders
are the most widely used of all rotary feedback devices. With the ease of solid state circuit and software design,
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