The primary effect of resolution on servo performance is the generation of noise. Lower resolution devices produce coarsely quantized position feedback, which in turn, produces coarsely quantized velocity feedback. For example, a 2048 line encoder sampled at 4000 Hz produces velocity quantized to about 30 rpm. The quantized feedback signals move through the servo controller and produce current spikes. These spikes, in turn, produce audible noise, heat, and torque perturbations. High-resolution feedback devices allow the servo system to avoid this problem.
This Application Note describes the various methods and combinations of methods for grounding and shielding. Following these recommendations will help minimize or eliminate problems encounters with electrical noise in your application.