The Auxiliary Power Unit Controller is based on agv’s RPC1210MG series of Electronic Engine Governors. Conventionally diesel engine governors sense and regulate the speed of the engine with respect to the load subjected to the engine. Of the various types of governors being used today, electronic governors have proven to be the best solution. Electronic governors have a few inherent advantages over mechanical governors: • No moving parts. • Less weight and bulk. • Can be mounted at a convenient distance away from the engine. • Acceleration, deceleration as well as load can be controlled easily by modifying the engine set-points. • A PID control can be easily implemented to provide rapid and accurate response while avoiding overshoot, under damping and oscillations in control action. • All the critical engine parameters which are monitored for the governing action can be logged for future references.