How to design the EMC interface of the motion controller MC expansion module?

The EMC design of the motion controller MC expansion module interface must consider connection reliability and noise isolation. The interface typically includes power, ground, control bus, and data bus. Power lines should be filtered by ferrite beads or π-type filters before entering the expansion module. Ground lines should ensure low-impedance connections, using multiple grounding points if necessary. High-speed data buses should be designed for differential transmission and impedance control. ESD protection devices should be added to each signal line at the interface connector.

Connectors should be selected with metal housings and locking mechanisms to ensure reliable mechanical and electrical connections. Backplanes or cables should provide good shielding. The expansion module itself should also have independent EMC filtering and protection. After design, the system-level EMC performance of the main controller and expansion module in the connected state must be tested to ensure that the expansion does not introduce new noise or reduce the original immunity. For hot-swappable expansions, special handling is required for power-on transients and ground potential balance.