How to choose between single-point grounding and multi-point grounding for motion controller MC

The choice between single-point and multi-point grounding for a motion controller (MC) depends on the signal frequency and system architecture. For low-frequency circuits, especially analog circuits and sensors, single-point grounding should be used to avoid low-frequency hum and interference introduced by ground loops, with all ground wires converging at a single power input point. For high-frequency digital circuits, communication interfaces, and RF circuits, multi-point grounding is essential, providing a low-impedance return path through a complete ground plane to prevent high-frequency signal radiation due to long ground wires.

In hybrid systems, a hybrid grounding strategy is often used: single-point grounding for low-frequency components and multi-point grounding for high-frequency components, connected at a single point by an inductor or ferrite bead. This component short-circuits under DC conditions to ensure single-point grounding and opens under high-frequency conditions to achieve separation. Safety requirements must also be considered during selection; protective grounding is typically single-point. Analyzing whether the highest frequency of the signal in the system and the length of the ground wires exceed 1/20 of the frequency wavelength can serve as a reference for selection.