Abstract: A measuring transmitter assembly using the same lines for power input and for output signals and using a single power supply, has a first power input and signal output loop coupled to the power supply, a second power input and signal output loop coupled to the power supply, a first sensor for providing a first input signal in response to the value of a first parameter and a second sensor providing a second input signal in response to the value of a second parameter, and a controller coupled to the first and second sensors. The controller is also coupled to the first and second power input and signal output loops and provides a first output signal on the first power input and signal output loop in response to the first input signal and a second output signal on the second power input and signal output loop. The second output signal may be in response to only the second output signal or it may be in response to the first and second input signals.

Abstract: An apparatus and method are provided for calibrating a measuring transmitter which provides an output signal proportional to a parameter of interest measured by a sensor in the measuring transmitter without removing the measuring transmitter from its normal operating position. The apparatus includes a housing, a calibration sensor element located in the housing for sensing said parameter of interest, and a tube for coupling the housing to the measuring transmitter, thereby exposing the calibration sensor to the same parameter of interest as the measuring sensor in the measuring transmitter.