In many cases, the encoder is not faulty, but only due to interference, resulting in poor waveform and inaccurate counting. May I ask how to make a judgment?


Encoders are precision components, mainly due to severe interference around the encoder, such as whether there is interference caused by frequent starting of large motors and welding machines, and whether they are transmitted in the same pipeline as the power line.


It is also important to choose what kind of output to counteract interference. Generally, anti-interference with reverse signal output is better, namely A+~A -, B+~B -, Z+~Z -, which is characterized by adding 8 power lines instead of 5 (zero in total). The transmission of reverse signals in elevators is symmetrical and less susceptible to interference. It can also be further evaluated in the receiving device (for example, when the receiving device's signal uses a 90 ° phase difference between A and B signals and reads four states of level 10, 11, 01, and 00, it is counted as an effective pulse. This scheme can effectively improve the system's anti-interference performance (accurate counting).


Even encoders have their own advantages and disadvantages. The internal circuit signal output of the encoder's electronic chip varies greatly. Otherwise, how could a 1000 line incremental encoder have such a large difference from over 300 to over 3000?


① Exclude (move, close, isolate) interference sources, ② determine if it is a cumulative mechanical gap error, ③ determine if it is a mismatch between the control system and encoder circuit interface (encoder selection error); ① ② ③ After the method compensation test, if the fault phenomenon is eliminated, a preliminary judgment can be made. If it is not ruled out, further analysis is required.


The simple method to determine whether it is a fault of the encoder itself is the troubleshooting method. The specific method of elimination is to replace it with an encoder of the same model. If the fault phenomenon is the same, it can be basically ruled out as an encoder fault problem, because the probability of two encoders having faults at the same time is very small and can be considered as 0. If a new encoder of the same model is installed and the fault is immediately eliminated, it can be basically determined that the encoder is faulty.