How to minimize the grounding impedance of the motion controller MC

Minimizing the grounding impedance of the motion controller (MC) is crucial for reducing ground noise voltage. A complete and continuous ground plane design should be adopted, with the ground plane placed on an inner layer in multilayer boards. Increase the number and density of grounding vias, especially around chip ground pins, filter capacitor ground terminals, and connector ground pins; ensure the quality of via diameter and copper plating. Use multiple parallel metal screws or conductive posts to connect the ground plane to the chassis ground, and apply conductive paste to reduce contact resistance.

Ground traces on the PCB must be short and wide, avoiding long and thin traces. For high-current loops, the ground trace width needs to be calculated based on the current, typically 1mm/1A. At the system level, the ground bus or ground bar must have sufficient cross-sectional area, and the connecting bolts must be tightened. DC grounding resistance can be measured using the four-wire method, and high-frequency grounding impedance can be measured using a network analyzer. The design goal is to maintain sufficiently low impedance from any point in the circuit to the reference ground point within the band of interest, typically requiring low impedance characteristics from MHz to GHz.