Absolute encoders principle！

Absolute encoders

      

Absolute encoders principle

Absolute rotary optical encoder, because each location is absolutely unique, interference, without power-down memory, has become increasingly widely used in various industrial systems point of view, the length of the measurement and positioning control.

There are many road reticle absolute encoder optical encoder, each groove successively with 2 lines, 4 lines, 8 lines, 16 lines. . . . . . Choreography, so that in every position of the encoder, by reading the engraved lines per channel through the dark, get a unique set of binary coded 2 ^ n-1 from zero to the power of 2's (Gray code), which is called n-bit absolute encoder. Such encoder is a mechanical encoder position determined, it is not a power outage, the impact of interference. Absolute encoder is determined by the mechanical position of the uniqueness of each location, without having to remember it, no need to find a reference point, and would not have to count, when you need to know where and when to go read its position. Thus, interference encoder properties, has greatly enhanced the reliability of the data.

Since the absolute encoder positioning clearly superior to incremental encoder, has been increasingly used in industrial targeting. Absolute encoders because of its high accuracy, the output bit more, if you still use parallel outputs, each of which an output signal of the need to ensure a good connection, but also for more complex conditions isolation, the number of multi-core cable connection, thereby inconvenience and reduced reliability, and therefore, the absolute encoder multi-bit output type, generally use the serial output or bus output, the German production of absolute encoder is the most common serial output SSI (synchronous serial line output).

Rotary single-turn absolute encoder to measure the rotation of each channel optical encoder engraved lines to obtain a unique code, when rotated more than 360 degrees, the encoding back to square one, which does not comply with the principle of an absolute encoder only, so the rotary encoder can only be used within the scope of measure 360 ​​degrees, known as single-turn absolute encoder.

If you want to measure more than 360 degrees of rotation, it is necessary to use multi-turn absolute encoder.

Encoder manufacturers use mechanical timepiece gear principle, when the center of the code wheel rotates through another set of code wheel gear (or sets of gear, multiple sets of code disk), single-turn encoder, based on the additional number of turns coding, to expand the measurement range of the encoder, absolute encoder so called multi-turn absolute encoder, it is also determined by the mechanical position encoders, position encoding each unique non-repetition, without memory.

Another advantage of the multi-turn encoder is due to the large measurement range, the actual use is often more affluent, so that the installation of unnecessary hard to find zero, as a starting point to an intermediate position on it, and greatly simplifies the installation difficult.

Multi-turn absolute encoder positioning advantage in length significantly, it has been increasingly used in industrial targeting.

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