What is multi-turn absolute encoder?

We need a lot of accessories in the actual application of the stepper motor, so that it can assist stepper motor work better. Encoder is a kind of hardware that we commonly use to adjust the working precision of stepper motor, to avoid the situation of lost step and overshoot in the work of stepper motor.

Encoders are mainly divided into incremental encoders and absolute encoders. Incremental encoders are divided into magnetic encoding and optical encoding. Absolute encoders are also divided into single-turn absolute encoders and multi-turn absolute encoders. We will only introduce the most complex encoder——multi-turn absolute encoder.

Multi-turn absolute encoder, as the name implies, absolute encoder is an encoder that can output absolute value. Compared with single-turn, the advantage is that after power failure, the motor can rotate in disorderly multi-turns, but it can still remember the original position. We know that the composition of the encoder includes: connecting shaft, code disc, light source and output circuit, etc. Therefore, the code disc of a multi-turn absolute encoder is very different from an incremental encoder. Please see the following figure:

The multi-turn absolute encoder (Absolute encoder) outputs a set of binary numbers. Its code disk is divided into many concentric channels, and each channel is called a "code channel". Each code channel has a separate output circuit to represent a binary bit. For example, in the above figure: the first bit (Bit1), the second bit (Bit2) and the third bit (Bit3) are in order, and the outermost code channel represents the 0th bit (Bit0). The greater the number of code channels, the greater the measurement range. The following figure is the waveform figure measured by the oscilloscope when the code wheel of the absolute encoder rotates:

Compared with incremental encoders, multi-turn absolute encoders are more suitable for applications such as manipulators. But the cost is more expensive. For details, please contact our engineers.


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