How to prevent interference in I/O module control cables?

Enhancing the immunity of I/O module control cables requires attention to selection, installation, and termination. First, shielded cables should be selected, ideally double-shielded cables with a braided layer and aluminum foil for superior shielding. Internal signal wires should use twisted pairs to suppress magnetic field interference. During installation, control cables must be run separately from power cables and high-current cables, with a minimum recommended spacing of 30 cm; if crossing is unavoidable, they should be perpendicular. Cables should be laid in metal cable trays or conduits, with multiple grounding points to create additional shielding.

At terminations, the cable shield should be properly grounded according to the aforementioned principles. For long-distance transmission, surge protectors, such as those used for RS-485 buses, can be installed at both ends of the cable. Ferrite rings can be placed at the cable entry point into the control cabinet to suppress high-frequency common-mode noise. For analog signal cables, active shielding drive technology can be considered, actively driving the shield potential to the same potential as the core signal to eliminate capacitive coupling. Regularly check the insulation and shielding integrity of the cables.