Where are the weaknesses of EPS conducted immunity (CS)?

The weaknesses of EPS systems in conducted immunity (CS, e.g., IEC61000-4-6) testing are typically those ports and internal circuits sensitive to RF interference injection. Key weaknesses include:

1. Power ports: Although generally equipped with filters, RF interference can still couple in if the filter's high-frequency performance is poor or grounding is inadequate.

2. Signal and communication ports: Ports such as RS485, CAN, and analog inputs can be easily injected with interference if they lack common-mode filtering or have improper filter parameters.

3. Long internal wires: Long, unshielded control or power lines inside the cabinet can act as receiving antennas, picking up interference and coupling it to sensitive circuits.

4. "Clean" side wiring after filters: If cables on the filter output side are parallel and close to input side cables, interference can bypass the filter through spatial coupling.

5. Poor grounding system: As mentioned earlier, poor grounding weakens the immunity of all ports. Improvements require strengthening filtering, shielding, and grounding in these areas.