Optical rotary encoder & magnetic rotary encoder！

Incremental encoder (rotary)

1, the working principle:

The optical encoder consists of a center axis of the optical encoder, which has a ring through the dark engraved lines, when the disk rotating at a pitch in the light emitting element is irradiated, the photosensitive member to obtain A, B signal is 90 degrees phase sine wave, this set of signals amplified by the amplifier and shaping, 90 degrees before the square wave output obtained, a compared to B phase conductor, the voltage amplitude is typically 5V. Let A former pilot phase when phase B is a positive direction of rotation, then the pre-B phase conductor A phase rotation direction is negative, the phase relationship between A and phase B of the encoder can determine the forward and reverse, C phase the reference pulse generating pulses, also known as zero pulses, which is the axis of rotation to generate a pulse in a fixed position, the encoder obtained zero reference position. AB-phase pulse signal by frequency - voltage conversion, got the shaft speed is proportional to the voltage signal can be measured velocity value and the amount of displacement.

The magnetic encoder is a new type of electromagnetic sensor developed in recent years, it is with the development of optical encoders developed. The main advantage of the optical encoder is moist gas pollution and sensitive, but poor reliability, and magnetic encoder less susceptible to dust and condensation impact, while its simple and compact structure, the high-speed operation, fast response (up to 500 ~ 700kHz), volume ratio of the optical encoder is small, lower cost, and easy multiple permutations and combinations of elements precisely, the new functional devices and multifunction devices easier to use an optical semiconductor element and magnetic components than composition. At high speed, high precision, small size, long life requirements, in the fierce market competition, the magnetic encoder for its outstanding characteristics and unique advantages, has become one of the key development of high-tech products.

Principle magnetic encoder is formed by a magnetic pulse train, generating a signal, characterized in that the rare earth magnetic powder unvulcanized rubber in a rubber mix forming the magnetic Pizi vulcanization adhered to the reinforcement ring (1), a magnetic rubber ring (2 ), on which the magnetic rubber ring to circumferentially alternately magnetized to produce S and N poles. At the same time using the new SMR (magnetic resistance) or Hall effect sensor as the sensing element, the signal is stable and reliable. In addition, the use of double-wiring process, but also the magnetic encoder only has the general only incremental encoder signal and incremental signal and the index signal output, also has absolute signal output. So, although currently accounting for about 90% of the encoders are optical encoders, but there is no doubt that in the future motion control systems, magnetic encoder amount will gradually increase.

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