CNC machine tool pulse encoder working principle - Database & Sql Blog Articles

The CNC machine tool pulse encoder is an optical position detecting component. The encoder disk is directly mounted on the rotating shaft of the motor to measure the rotation angle position and speed of the shaft. The output signal is an electric pulse.
The characteristics of this detection method are: non-contact type, no friction and wear, small driving torque and fast response speed. The disadvantage is poor anti-pollution ability and easy damage. According to its coding method, it can be divided into incremental and absolute values.

According to the detection principle, the encoder can be divided into optical, magnetic, inductive and capacitive. According to its scale method and signal output form, it can be divided into three types: incremental, absolute and hybrid.
Incremental Encoder working principle Incremental rotary encoder converts the timing and phase relationship of its angle code wheel through two internal photosensitive receiving tubes, and obtains an increase in the angular displacement of the angle dial (positive direction) or decrease (negative direction). .
The internal working principle of the incremental rotary encoder

The two points A and B correspond to two photosensitive receiving tubes, the spacing between the two points of A and B is S2, and the grating spacing of the angular code discs are S0 and S1, respectively.
The output waveform diagram shows that the timing of each motion cycle is

Clockwise movement counterclockwise movement AB
1 1
0 1
0 0
1 0A B
1 1
1 0
0 0
0 1 This way, the AB phase can know the current direction and speed of the encoder.

Absolute Encoder Operation Principle There are many optical channel engraving lines on the absolute encoder optical encoder. Each line is followed by 2 lines, 4 lines, 8 lines, and 16 lines. . . . . . Orchestration, so that at each position of the encoder, by reading the pass and dark of each reticle, a set of unique binary codes from the zeroth power of 2 to the n-1 power of 2 is obtained (Gray Code), this is called an n-bit absolute encoder. Such an encoder is determined by the mechanical position of the optical code disc, and it is not affected by power outages and interference.
Absolute encoders are unique in each position determined by the mechanical position. They do not need to be remembered, do not need to find a reference point, and do not have to count all the time, when to know the position, and when to read its position. In this way, the anti-jamming characteristics of the encoder and the reliability of the data are greatly improved.