How to rectify EMC issues caused by MC communication interruption in motion controllers

EMC remediation for communication interruptions in the motion controller (MC) requires identifying the type of interference and coupling path causing the interruption. First, reproduce the interruption phenomenon, for example, during EFT or surge testing. Use an oscilloscope to monitor the communication signal lines and power lines, capturing any waveform anomalies at the moment of interruption. Use a near-field probe to scan the controller and cables to locate strong radiation sources or sensitive points.

Common causes include: common-mode noise causing transceiver misjudgment, drastic ground potential fluctuations, power supply drops, and insufficient response or malfunction of port protection devices.

Remedial measures may include: strengthening port common-mode filtering, such as increasing the inductance of the common-mode choke; improving the connection between communication ground and other grounds; adding decoupling capacitors or voltage regulators to the communication chip power supply; replacing with a faster-responding TVS diode; and optimizing the grounding of the communication cable shield. Retest after each modification until communication no longer interrupts under interference. Remediation requires systemic analysis to avoid blindly replacing components.