How to suppress interference at the MC encoder interface of the motion controller

Suppressing interference at the MC encoder interface of a motion controller requires addressing power supply, signal transmission, and grounding. Provide a clean, isolated power supply to the encoder, or add LC filters to the power lines. Use high-quality twisted-pair shielded cables for the encoder's differential signal lines, with the shield grounded at a single point on the controller side. At the controller interface, install a common-mode choke, such as the CML series, for each pair of differential signals to suppress common-mode noise. Connect low-capacitance TVS diodes, such as the ESDLC series, in parallel to provide transient protection.

On the PCB layout, the encoder receiving circuit should be kept away from noise sources, and its power supply should be isolated via a ferrite bead. For single-ended encoder signals, add Schmitt trigger shaping and RC filtering at the receiving end. Check that the grounding between the encoder and controller is consistent to avoid interference introduced by ground potential differences. Through testing under interference environments such as motor operation, monitor the waveform and counting stability of the encoder signal to verify the suppression effect.