How should the encoder cable shield be grounded?

The grounding method of the encoder cable shield directly affects its shielding effectiveness and the risk of ground loops. Etymotic's best practice is to use a hybrid grounding method: single-point grounding at the driver end and capacitive coupling at the motor end. At the driver end, the shield is directly connected to the driver's metal housing (shielding ground) via a metal connector shell or a crimp-type shielding clip in a 360-degree connection. At the encoder connector at the motor end, the shield is not directly connected to the motor housing, but rather connected via a Y capacitor (e.g., 2.2nF/Y1). This allows high-frequency interference noise to be discharged to the motor housing through the capacitor, while the power frequency or low-frequency ground potential difference is blocked by the capacitor, avoiding ground loop currents. Simultaneously, ensure the cable shielding coverage is >85% and maintain shielding continuity at the connector connection. This grounding method has been tested and provides >40dB of shielding effectiveness in the 30-100MHz frequency band, with a measured loop current on the shielding layer of <1mA.