How to improve shielding when grounding the enclosure of an HMI (Human Machine Delivery) system?

Improving the grounding quality of the HMI enclosure is crucial for enhancing its overall shielding effectiveness and immunity. Enclosure grounding is not only for safety but also provides a low-impedance discharge path for interference currents. The grounding point should be located near major interference entry points or sensitive areas, such as power inputs and areas with concentrated communication ports. Grounding connections must ensure low impedance and long-term reliability. Dedicated grounding terminals or grounding screws should be used, and short, wide braided copper strips or flat copper wires should be used for the connecting conductors. Paint should be removed from the connections, and toothed washers should be installed. For enclosures composed of multiple parts, each part should be connected to the main grounding point via a low-impedance path to ensure a consistent potential across the entire enclosure.

Internally, the PCB ground plane should be connected to the enclosure at multiple points, especially near I/O ports and filters, using metal brackets, conductive foam, or grounding springs. For high-frequency grounding, the spacing between connection points should be less than 1/10 of the highest frequency wavelength requiring shielding to avoid the "incomplete grounding" effect. At the system level, the grounding terminal of the HMI device must be reliably connected to the grounding busbar of the mounting cabinet. A robust, low-impedance enclosure grounding system is essential for effectively dissipating internal noise and guiding external interference to the ground, thus ensuring the effectiveness of shielding measures. Etymotic's grounding connection components and conductive materials provide strong support for constructing high-quality enclosure grounding systems.