Absolute encoder features and classifications！

Absolute encoder (rotary)

Incremental encoder output pulse is rotated by counting device knows its location, when the encoder does not move or power outage, counting on internal memory to remember the location of the device. Thus, when the power failure, the encoder does not have any movement, when work calls, encoder output pulse process, it can not have lost the pulse interference, otherwise, it will count zero offset memory device, and this bias the amount of shift is no way to know in order to know the results only after the production error appears.

The solution is to increase the reference point, the encoder after every reference point, the reference position correction position count into the memory device. In the previous reference point, we can not guarantee the accuracy of the location. To this end, every operation in the industrial in there to go first reference point, turn the change and other methods.

For example, the positioning of the scanner printer to use an incremental encoder principle, each boot, we can hear Pilipala while sound, it was looking for a reference zero before work.

Such methods for some industrial projects too much trouble, not even allowed to give change boot (boot will know the exact location), so there is an absolute encoder appears.

1, the working principle:

There are many road reticle absolute encoder optical encoder, each groove successively with 2-wire, 4-wire, 8-wire, 16 wire ...... choreography, so that in each position encoder, engraved by reading each channel line through the dark, get a group from the n-1 th power of only binary coding (Gray code) to 2 2 to the zero power, 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.

Uniqueness of each absolute encoder position determined by the mechanical position, it does not require power-down memory, 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, greatly improving the reliability of the data.

Since the absolute encoder positioning obviously superior to incremental encoder, has been increasingly used in various industrial systems point of view, length measurement and positioning control. However, because of high-precision, large output bits, if you still use parallel outputs, each of which is connected an output signal of the need to ensure good working conditions but also for more complex isolation, multi-connection cable core number, which brought a lot of inconvenience and reduce the reliability, therefore, absolute encoder multi-bit output type, generally use the serial output or bus output.

2, from single to multi-turn absolute encoder absolute encoder:

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, so not only in line with the principle of an absolute encoder, such rotary encoder can be used only 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 central rotary encoder, 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 encoder measuring range, this absolute encoder is called multi-turn absolute encoder, it is also determined by the mechanical position encoders, each encoding a unique position will not be repeated, without memory.

Another advantage of the multi-turn absolute 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 and commissioning difficulty.

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

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