Incremental coding In addition to the ABZ signal of the ordinary encoder, the incremental servo encoder also has the UVW signal. Most of the domestic and early imported servos use this form, and the lines are more.
The incremental encoder outputs a pulse when it is rotated, and its position is known by the counting device. When the encoder is not moving or power is off, it depends on the internal memory of the counting device to remember the position. In this way, when the power is cut off, the encoder can't have any movement. When the caller works, the encoder can not interrupt and lose the pulse during the output pulse. Otherwise, the zero point of the counting device will be offset, and the bias will be offset. The amount of shift is unknown, and only the wrong production result can be known.
The solution is to increase the reference point, and the encoder corrects the reference position into the memory position of the counting device every time the encoder passes the reference point. Before the reference point, the accuracy of the position cannot be guaranteed. For this reason, in the industrial control, there are methods such as finding a reference point for each operation, and starting to change the zero.
Absolute rotary photoelectric encoders have been widely used in angle, length measurement and positioning control in various industrial systems because of their absolute uniqueness, anti-interference and no need for power-down memory.
There are many scribe lines on the absolute encoder disk. Each line is followed by 2 lines, 4 lines, 8 lines, and 16 lines. . . . . . Arrange 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), which is called an n-bit absolute encoder. Such an encoder is determined by the mechanical position of the code wheel and is immune to power outages and interference.
Absolute encoder uniqueness of each position determined by the mechanical position, it does not need to remember, no need to find a reference point, and do not have to count all the time, when you need to know the position, when to read its position. In this way, the anti-interference characteristics of the encoder and the reliability of the data are greatly improved.