How can the grounding impedance of an intelligent low-voltage monitoring unit be minimized?

To minimize grounding impedance, a multi-layer parallel and short-path design is employed. The chassis grounding uses a 16mm² copper strip, less than 0.3m in length, with a DC resistance of less than 0.8mΩ. The internal grounding wire uses a star topology, with a wire diameter of 1.5mm² and a length of less than 80mm. The PCB grounding layer uses 1oz thick copper, connected via multiple vias. Grounding points use metal screws with star washers. High-frequency grounding uses a PBZ1608E600Z0T ferrite bead connected in parallel with a 0.1μF capacitor. With this design, the grounding impedance in the DC-100MHz frequency band is less than 0.2Ω, and the electrostatic discharge time is less than 2ns, meeting the IEC 61000-4-2 fast discharge test requirements.