The difference between incremental encoder absolute encoder

Compared with the “incremental encoder”  the “absolute encoder”, the “absolute encoder” of the servo drive uses a certain method to express  memorize the absolute position, angle  number of revolutions of the object. In other words, once the position, angle  number of turns are fixed, the value of the encoder is uniquely fixed at all times, including power-on after power failure.

"Incremental encoders" cannot do this. Usually, the "incremental encoder" outputs two A, B pulse signals  a Z (L) zero signal,  the phase angle of the A  B pulses is 90 degrees. The position, angle  increment of the number of revolutions can be known through pulse counting,  the direction can be known through the advance  lag of the A  B pulse signals. After a power failure, counting must be restarted  the agreed benchmark.

"Incremental encoder" refers to the need to post-process the position, angle  number of revolutions,  then turn on the power again to perform a "reset" operation. Therefore, the "incremental encoder" of the servo drive is more effective than the "absolute encoder". The price is much cheaper.

1 Encoder classification

According to the detection principle, encoders can be divided into optical encoders, magnetic encoders, inductive encoders  capacitive encoders. According to its scaling method  signal output form, it can be divided into incremental type, absolute type  mixed type.

1 Incremental encoder The incremental encoder directly uses the photoelectric conversion principle to output three sets of square wave pulses A, B,  Z phases,  the phase difference of the A  B pulses is 90. , Make the direction of rotation easy to judge, Z phase is one pulse per revolution, used for reference point positioning. Its advantages are simple structure, average mechanical life of more than tens of thousands of hours, strong anti-interference ability, high reliability,  suitable for long-distance transmission. The disadvantage is that the absolute position information of the shaft rotation cannot be output.

2 Absolute encoder An absolute encoder is a sensor that directly outputs numbers. There are several concentric code discs along the radial direction on its circular code disc,  each track is composed of transparent  opaque sectors. The sector trees of adjacent code channels have a dual relationship. The number of code channels on the code wheel is a binary number. The optical disc has a light source on one side,  a photosensitive element corresponding to each encoding channel on the other side. When the disc is in different positions, each photosensitive element converts the corresponding level signal into a binary number according to whether it receives light. The feature of this encoder is that it does  require a counter  can read a fixed digital code corresponding to the position at any position of the axis. Obviously, there must be N kinds of theories. At present, there are 16-bit absolute encoder products in China.

three. Hybrid absolute encoder The hybrid absolute encoder outputs two sets of information. One set of information is used for detection  has an absolute information function; the other set of information is exactly the same as the output information of the incremental encoder.

DEUPREE (Qingdao) Industrial Technology Co., Ltd. is an integrated enterprise focusing on the research  development of automated industrial technology  equipment manufacturing. The company’s products mainly include rotary motion sensors, linear displacement sensors, object recognition sensors, laser rangefinders,  process control measurement Class instruments, signal detection systems, signal transmission systems, immature drive systems, UPS safety power supply systems,  automation equipment energy-saving cleaning auxiliary equipment systems are  limited to this, we can also customize  flexibly customize according to customer needs to meet different Different needs of customers.