The reliable transmitter with available dual sensor input


SITRANS TH320/TH420 is designed to support all common resistance thermometers and thermocouples. It also evaluates resistance and millivolt signals. Setup is quick and easy with SIMATIC PDM or the Handheld Communicator.

The true reliability of the SITRANS TH420 is exemplified by the dual sensor input with 4-wire sensor connection and hot backup function. In case of a sensor failure, the transmitter seamlessly switches to the second sensor, so that the data is recorded continuously and without any loss.

The sensor trim realized following the Callendar-Van-Dusen-Method as well as the additional function of the sensor drift detection (SITRANS TH420 only) allows a high accuracy, accelerated calibration time and optimized calibration planning.

The SIL2/3 certificates in combination with a broad range of ex and marine approvals are the perfect solution for your safety-critical applications, also under harsh conditions up to -50°C.

User-friendly details give SITRANS TH320/TH420 its uniqueness: Without opening the 4-20mA loop, the output current can be read out directly with a multimeter. A red/green LED shows the technician the status at a glance.




Resistance thermometers, Thermocouples, Resistance-type sensors, DC sources


4 to 20mA (SITRANS TH320),  HART (SITRANS TH320/420)


  • High availability during measurement

  • High reliability and long-term stability

  • Avoidance of production stop because of measurement failures

  • Best cost-benefit ratio for facility management

  • Cost reduction through anticipatory maintenance

  • High sensor accuracy

  • Extended temperature range up to -50°C + SIL2/3 approvals

TH420 3 Dimensional View

Check out the SITRANS TH420