How to design the EMC of motion control function in a smart controller PAC?

The EMC design for the motion control function of the intelligent controller PAC needs to address key signals such as pulse output and encoder feedback. The pulse output uses differential drive (e.g., LVDS) with a common-mode inductor (CMZ20212A-900T) to suppress common-mode radiation. The encoder feedback uses differential reception with RC filtering and a TVS (ESDLC5V0D3B) at the input. The power supply provides independent power to the motion control circuit and uses a ferrite bead (PBZ1608A-102Z0T) for isolation.

In terms of PCB layout, the motion control area is kept away from noise sources and uses a complete ground plane. In terms of software, an error compensation algorithm is used to reduce interference. During testing, the motion control accuracy must meet the requirement of a positioning error of less than ±1 pulse under interference (e.g., EFT 4kV). Through this design, the PAC motion control function meets the IEC61800-3 standard and is suitable for industrial environments.