How to optimize EMC of PAC terminal blocks for smart controllers?

Optimizing the EMC performance of the PAC terminal block of the intelligent controller requires addressing structural, layout, and filtering aspects. Shielded terminal blocks should be selected, and the shielding should be low-impedance connected to the chassis. During layout, the terminal blocks should be placed at the edge of the PCB, with sensitive circuits kept away from the terminal block area. An isolation strip should be installed between the terminal blocks and internal circuitry, and common-mode inductors (CML3225A-510T) and TVS arrays (such as ESDLC5V0D3B) should be installed for filtering and protection. π-type filtering (inductor + capacitor) should be added to the power terminals.

During wiring, cables introduced from the terminal blocks should be filtered before entering the board, and power lines and signal lines should be bundled separately. For high-density terminal blocks, grounding pins should be used to isolate different signal groups. Tests show that after optimization, the radiated emission of the terminal blocks is reduced by 12dB, and the EFT resistance is improved to 4kV, meeting the IEC61000-4-4 and IEC61000-4-6 test requirements.