The GM-A is a cost-efficient digital readout that works with amplified (0 V to 5 V or 4 mA to 20 mA) transducers or transmitters. This unit supplies power to the sensors. Two-wire current is user jumper selectable for use with two-wire current transducers. Separate power supply required for three-wire current use. Not for use with intrinsically safe applications utilizing a barrier.