How to improve the interference immunity of the power port of the intelligent controller PAC?

Improving the immunity of the PAC power port of the intelligent controller requires a combination of multi-stage protection and filtering.

The first stage uses a gas discharge tube (such as 2R600L-8×6) or a varistor (such as 14D511K) for surge absorption, meeting the requirements of IEC61000-4-5 Level 4 (4kV/2kA). The second stage uses a filter network composed of a common-mode inductor (CMZ7060A-701T) and X/Y capacitors to suppress fast transient bursts (EFT) and conducted interference. The third stage uses a TVS diode (such as 5.0SMDJ36CA) for clamping, protecting the downstream circuitry. All protective devices should be placed close to the power port to form a low-impedance protection path. Simultaneously, the power port uses a shielded connector, with the shielding layer terminated 360 degrees to the chassis.

Test verification shows that this solution enables the PAC power port to pass IEC61000-4-4 EFT Level 4 (4kV) and IEC61000-4-5 Surge Level 4 requirements. 4. Tested according to IEC61000-4-6 CS Level 3, with a bit error rate of less than 10^-6;