The head transmitter KTM AG for connection to a resistance thermometer Pt100 is a temperature transducer for measuring and monitoring temperatures in the range from –100°C up to +600°C with a measuring range between 20 Kelvin and 700 Kelvin.
The temperature head transmitter KTM AG can be installed in a connection head (form B) or in a field housing.
A constant current from an integrated current source is feed to a 2- or 3-wire Pt100 resistor that is installed in a sensor. This current leads to a voltage drop at the Pt100, that becomes higher or lower, dependent on the measured medium temperature. The produced resistance proportional voltage signal is measured by the transmitter and is than linearized and converted into a constant current signal 4...20mA.
The measured voltage signal of the Pt100 is supervised and in the case of sensor breakage a failure information is produced on to the 4...20mA signal. The output signal rises in that case to 21,7 mA. At a sensor short circuit the signal goes to 3,55 mA.