Driving the amp gauge from the DSE kit was easier than I anticipated – the DSE kit does not use a number of pins on the 16F877A – simply configuring one of these for PWM was all that was needed. I removed the ULN2003’s from the circuit and are just driving the output directly from the microcontroller via the pullup resistor. I’ve added an extra control command which simply varies the duty cycle and I can make the gauge read from 0 to 300A with all points in between.

Picture below – this really needs a movie which I’ll upload later.

Simulator Construction - Amp gauge control working