How does the PAC expansion module of the intelligent controller affect EMC?

Expansion modules (such as I/O modules and communication modules) of the intelligent controller PAC may introduce additional noise, affecting the overall EMC. Power supply noise, signal crosstalk, and poor shielding of expansion modules can couple to the main controller through the backplane. To reduce the impact, expansion modules should be filtered independently, and common-mode inductors (CML3225A-510T) should be used for isolation at the backplane interface.

Backplane wiring should be standardized to avoid long parallel traces. During testing, the system should be configured to the most complex state (all modules at full load) for overall EMC testing. If expansion modules cause exceedances, individual module modifications are required. The main controller should be designed with sufficient filtering and shielding margins to accommodate a certain number of expansion modules.