How to isolate the communication ground of the motion controller MC

The communication ground of the isolated motion controller (MC) is designed to prevent communication failures or hardware damage caused by ground potential differences between different devices. For electrical communication interfaces such as RS485, CAN, and Ethernet, isolated transceiver modules or chips are used, which integrate signal and power isolation. The isolation voltage is selected according to the application environment, typically from 1.5kV to 3kV. A separate isolated power supply must be provided for the isolation side, which can be achieved using an isolated DC-DC module.

On the PCB, the isolation device is connected across an isolation strip, with the ground planes on both sides completely separated. For fiber optic communication, electrical isolation is naturally achieved. After isolation, whether the shielding layer of the communication line should be connected to the ground on the isolation side at the controller end or to the chassis ground depends on the system grounding strategy. After design, withstand voltage and insulation resistance tests must be performed to verify whether communication can proceed normally in the presence of ground potential differences. Isolation is one of the ultimate solutions to ground loops and common-mode interference.