These transmitters accept 4-20mA process current inputs from a DCS and provide isolated 4-20mA outputs to resistive loads (e.g. a valve). Each channel is isolated from the others to prevent interaction between the channels. Power for the transmitters is taken from the two wire 4-20mA input signal. For fast trouble shooting each unit has LEDs and diagnostic test points. Power LEDs help identify open circuits in the output loop, whilst a 10Ohm precision resistor enables monitoring of the output signal without disturbing the field wiring.