How to protect the EMC of the digital I/O port of the motion controller MC?

EMC protection for the digital I/O ports of the motion controller MC requires port filtering, transient protection, and proper grounding. A ferrite bead or small resistor should be connected in series on each I/O line, and a capacitor should be connected in parallel to ground to form a low-pass filter to remove high-frequency noise. A TVS diode array, such as the ESDLC series, should be connected in parallel to provide ESD and EFT protection. For input ports, Schmitt triggers can be used for shaping. For output ports driving inductive loads, freewheeling diodes must be added. All I/O port filtering and protection devices should be placed close to the connectors.

On the PCB layout, the ground plane of the I/O area should be complete and connected to the chassis or motherboard ground through multiple vias. Shielded cables should be used to connect external devices, with the shield grounded at the controller end. Immunity tests such as ESD, EFT, and surge tests should be conducted to verify the stability of the I/O ports under various transient interferences. For high-density I/O, connector modules with integrated filtering and protection functions can be used.