An automatic sensor excitation voltage adjustment feature, a multi-range concentration feature, a single calibration feature and a barrier circuit feature. The automatic sensor excitation voltage adjustment feature includes a transmitter having a transmitter microprocessor that provides an initial voltage to a sensor having a sensor microprocessor. As the voltage changes a correction signal is relayed from the sensor microprocessor to the transmitter microprocessor. The correction signal is used to adjust the voltage applied to the sensor. The multi-range concentration sensor feature includes an amplifier associated with the sensor/microprocessor to create gain settings used to optimize sensor resolution by changing a gain value for the sensor. This enables use of a single sensor for a variety of different concentration ranges. The single calibration feature enables a sensor to be calibrated at a single gas concentration value, and thereafter be used for a variety of different concentration range applications. The barrier circuit feature provides for intrinsically safe power and communication signals to the sensor.