How to filter the power supply of the motion controller MC encoder

Effective filtering of the encoder power supply for the motion controller MC is a prerequisite for ensuring its signal quality. If the encoder is powered by the controller's internal power supply, an LC filter should be added at the power output. PBZ series ferrite beads or power inductors can be used, and a combination of low-ESR MLCCs and electrolytic capacitors should be employed to filter out switching noise and ripple on the power board. Ideally, an independent isolated DC-DC module should be used to power the encoder, fundamentally cutting off the common-mode noise path.

A common-mode choke should be connected in series on the power supply line to suppress common-mode interference introduced by long cables. At the encoder end, a large-capacity electrolytic capacitor should be connected in parallel at the power input for energy storage and low-frequency filtering, followed by a small-capacity MLCC for high-frequency filtering. The grounding terminals of all filter capacitors should be connected to the encoder cable shield or the encoder housing. The filtering effect should be verified by measuring the ripple and noise on the encoder power supply pins to ensure stability when exposed to interference sources such as motors.