For temperature measurement using thermocouples, a reference value is always needed and/or a compensation must be made. Thus, there is a sensor built into the digital transmitter (Pt100) which measures the terminal temperature (ambient temperature). (cold junction, CJC, cold junction compensation). Thermocouple connection is always 2-wire. (Caution: do not swap over the plus and minus!) No sensor short circuit monitoring is available (only sensor break monitoring) Transmitters with galvanic isolation are strongly recommended (WIKA Models T12, T32, T53).