How should shielding be handled for industrial servo control cables?

The shielding of servo control cables (such as enable, alarm, and analog commands) must balance interference immunity and radiation protection. Audiotech's approach: Use multi-core shielded cables, with twisted pairs for each differential or sensitive signal pair. The overall cable shield uses a composite shield of aluminum foil and braided mesh, achieving a shielding effectiveness >90dB. The shield is grounded at both the controller (e.g., PLC) and device (servo drive) ends, but in slightly different ways: at the relatively quiet controller end, the shield can be directly connected to the chassis; at the noisier drive end, the shield is connected to the chassis through a capacitor (e.g., 1nF/Y1) or an RC network (e.g., 100Ω+1nF) to discharge high-frequency noise while suppressing low-frequency loops. For analog command lines, an RC low-pass filter (e.g., 1kΩ+100nF) can be added at the drive input. Properly shielding control cables can suppress interference voltage induced by motor switching noise to below 50mV, ensuring the accuracy of control commands.