How to suppress interference from long power FTU cables?

For interference suppression of long cables (>10m), transmission line effects must be considered. Shielded twisted-pair cable with characteristic impedance matching (e.g., 120Ω for RS485).

Termination matching: Parallel connection of a 120Ω resistor.

Repeaters: Add signal repeaters every 500 meters to restore signal quality.

Common-mode filtering: Add CMZ3225A-510T common-mode inductors at both ends of the cable.

Protection: Install ESDSM712 protection at both ends.

Cabling: Keep away from interference sources, with a distance of more than 300mm from power lines.

Through suppression, the bit error rate of long cable transmission is less than 10^-6, meeting the IEC 61000-4-5 4kV surge test requirements.