The BRT143 is primarily resistance or slide-wire transmitter designed for 2 or 3-wire resistance input with a standard process signal output. The resistance change is detected by applying a constant current to the field device which will result in a change of voltage on change of resistance. Two current ranges are available to suit the magnitude of resistance change. For resistances up to 100Ω, a fixed 20mA current source is supplied as the excitation. For resistances above 100Ω, a current excitation is supplied of a value to develop 2V across the input resistance at maximum value. Final calibration is trimmed using the front accessible ‘offs’ and ‘span’ 15-turn trim adjustments. Lead breakage will cause the output to increase to maximum. The output signal level is indicated by LED on the front giving clear indication of module function, presence of signal and output loop closed (for current outputs only). RF and power transients protection is also standard as with all BASI modules. Various power supply choices are available ranging from 240Vac down to 8Vdc, all provide power isolation. Sensor input and output can be isolated by selecting option 8.