In this paper, we develop a digital PID controller for galvanometric low inertia scanner. The controller consists of software for PID control algorithm and hardware such as demodulation circuit, automatic gain control circuit and galvanometer driving circuit. A problem with time delay due to analog to digital conversion in the digital controller is improved by using Feed-Forward controller. The actual gain is selected through computer simulation and has been tested on a General Scanning Model M3 galvanometric scanner equipped with the developed control hardware for a various kind of signals : sawtooth, sinusoidal and rectangular. From the real experiments to track reference signals, the digital PID controller shows a comparable performance to the analog PID controller of General Scanning Model M3.
