How to handle the shielding layer of I/O module cables?

Properly handling the shielding layer of I/O module cables is crucial for ensuring its shielding effectiveness. The shielding layer must achieve a complete 360-degree termination at the connector, meaning it must be evenly pressed onto the connector's metal housing or a dedicated shielding clip, forming a circumferential contact and avoiding a "pigtail" connection. The connector's metal housing should achieve low-impedance metal-to-metal contact with the module housing or mounting plate. For cable entry points, shielded cable glands can be used. If the cable needs to enter the PCB, the shielding layer should be pressed onto the PCB's ground copper surface using a metal clamp, which should be connected to the internal ground plane through multiple vias. The shielding layer should not be used as a return conductor for signals. For multi-core cables, if there are separate shielding layers, they should be separated from the main shielding layer at the connector end by insulation, or connected together as required by the equipment. After processing, a multimeter should be used to measure the resistance between the shielding layer termination point and the module ground point to ensure a good connection. Furthermore, care should be taken to ensure that no wire burrs puncture the insulation at the shielding layer termination point, causing a short circuit.