How to determine if an encoder is counting accurately

In many cases, the encoder is not broken, but the interference causes a bad waveform, which leads to (generates, contributes to) inaccurate counting. How can I determine this? Encoder is a precision component, this is mainly because of the encoder around the interference is more serious, such as: whether there is a large motor, welding machine frequent start-up caused by interference, and whether the power line and the same pipeline transmission and so on.

Select what kind of output on the anti-interference is also very important, the general output with reverse signal anti-interference to be better, that is, A + ~ A-, B + ~ B-, Z + ~ Z-, which is characterized by the addition of the power supply (to the electronic equipment to provide power to the device) 8 wires, rather than 5 wires. Examples include various lifting devices, feeder trolley positioning, etc. With the reverse signal in the cable (Cable) in the transmission is symmetrical, subject to interference is small, in the receiving device can also be added to the judgment.

That is, the encoder is also good and bad, its code disk \ electronic chip (also known as microcircuit) \ internal circuit \ signal output varies greatly, otherwise how a 1000-line incremental encoder will be from more than 300 yuan to more than 3000 yuan difference is so big?

① Excluding sources of interference.

② Judge whether the accumulated deviation of the mechanical clearance

③ Determine if there is a mismatch between the control system and the encoder's circuit interface;

Repayment of the test after the fault phenomenon excluded, it can be initially judged, if not excluded must be further analyzed. Binary encoder to determine whether the encoder's own fault is a simple method of elimination. The specific method of elimination is: replace the encoder with a same model, if the same failure phenomenon, can be basically ruled out is the problem of encoder failure (Emerson), because the two encoders at the same time there is a failure of small probability of events may be very small, can be viewed as 0. If you change the same type of encoder up, the failure phenomenon is immediately ruled out, then can be basically determined to be the encoder failure.