Did the conducted immunity test of the RS485 interface of the BMS control board result in data transmission errors?

Data transmission errors occurred in the conducted immunity test of the RS485 interface, indicating that interference had breached the interface protection. Solutions include adding a TVS diode array to ground on the A/B lines to suppress transient overvoltages; adding a common-mode choke in series at the bus entry point to improve common-mode immunity; ensuring proper matching of the 120Ω terminating resistors; and ensuring strictly equal-length, tightly coupled differential lines for balance. Using an isolated RS485 transceiver can break ground loops and significantly improve immunity. Additionally, ferrite beads and capacitors are provided for the transceiver power supply for filtering. By comprehensively applying port protection, filtering, isolation, and good wiring practices, the interference immunity of the RS485 interface can be effectively improved.