Encoder A, B, Z phase and their relationship

What is the relationship between A-phase, B-phase signal, Z-phase signal, U-phase signal, V-phase signal, and W-phase signal of TTL encoder?

To answer this question, we explain from the following aspects: The encoder only has the concept of A-phase, B-phase, and Z-phase signals.

The so-called U-phase, V-phase, and W-phase refer to the three-phase AC power supply of the main power supply of the motor, which has nothing to do with the encoder. "A-phase, B-phase, Z-phase" and "U-phase, V-phase, W-phase" are two concepts that have nothing to do with each other. The former is the encoder channel output signal; the latter is the three-phase main circuit of the AC motor powered by.

In the A-phase, B-phase, and Z-phase signals of the encoder, the signals of the A and B channels are generally quadrature (that is, 90° mutual difference) pulse signals; and the Z-phase is a zero pulse signal.

In detail, except for the output signal of the general encoder, except for the two phases A and B (the phase difference of the signal sequence of the two channels A and B is 90 degrees), a zero pulse Z is also output per revolution. When the spindle rotates in a clockwise direction, the output pulse A channel signal is before the B channel; when the spindle rotates counterclockwise, the A channel signal is after the B channel. Therefore, it is judged whether the main shaft is rotating forward or backward. In addition, the encoder sends a pulse every revolution, which is called zero pulse or identification pulse (ie Z-phase signal). The zero pulse is used to determine the zero position or the identification position. To accurately measure the zero pulse, regardless of the direction of rotation, the zero pulse is output as the high-order combination of the two channels. Due to the phase difference between the channels, the zero pulse is only half the pulse length. Encoders with U, V, and W phases should be servo motors. The A and B phases of the encoder should be two pulses, or sine wave, or square wave. The phase difference between the two is 90 degrees, so it can measure the speed or Measuring the rotation direction of the motor, the Z phase is the reference pulse, one pulse is output per revolution, and the pulse width usually only occupies 1/4 cycle. Its function is for the encoder to self-calibrate, so that the encoder will be powered off or lose pulses. It can also be used normally. ABZ is the position signal of the encoder, and UVW is the magnetic pole signal of the motor, which is generally used for synchronous motors; AB For TTL/HTL encoders, the AB phase is different according to the encoder's subdivision, and there are many per revolution, but Z There is only one phase per revolution; the phase difference between the UVW magnetic pole signals is 120 degrees, and it rotates with the angle of the encoder. It can be said that there is no direct relationship with ABZ.