Introduction to the parameters of special encoder
Refers to the smallest unit that the encoder can distinguish.
Incremental encoder, its pixels represent the number produced by one rotation of the encoder shaft, that is, the expression number/(Pulse Revolution). The number of lines through the lamp slot on the code wheel forms a circle, which is also called the distribution of how many lines, and the common ones are 5-6000 lines. Absolute encoder, the internal code disk uses its independence, the unit is bit (bit), the specific is also divided into single-turn, used to sum multi-turn absolute.
2. High precision
First, make it clear that experts and the earth are two different concepts.
Accuracy refers to the greatest significance between the encoder's reading and the actual position of the shaft, and is usually expressed in angles, arc minutes or arc seconds. For example, the absolute encoder parameter table will write ±20”, which means the performance of plus or minus 20 arc seconds between the output reading of the encoder and the actual position of the shaft. Accuracy is determined by various factors such as code wheel engraving processing, precise shaft concentricity, temperature characteristics of materials, and circuit response time.
3. Maximum response frequency
Refers to the number of sentences output by the encoder, the unit is Hz. The calculation formula is:
Maximum response frequency = resolution * shaft size / 60
For example, the accuracy of the encoder of a motor is 100 (that is, there are 10 grating revolutions in one revolution of the photoelectric code disk), and the time per axis is 120 (that is, 2 revolutions per second), then the response frequency is 100*120/60 = 20Hz, The programmer outputs 200 sounds (the motor programmer has rotated 2 times).
4. Signal output form
For each incremental encoder, the signal of the output circuit is independent, and the output circuit usually has integrated light-emitting open-circuit output, push-pull output, emission output, etc. Absolute encoder, because it is a direct output of dozens of binary numbers, in order to ensure the transmission rate and quality, generally use spark output or bus type output, such as spark interface (SSI), RS485, CANopen or EtherCAT, etc., there is also a One is parallel output, and the output circuit form is the same as the incremental encoder.