SITRANS TR420 transmitters with two inputs can use in all sectors. Their compact design enables simple mounting on standard DIN rails on-site in protective boxes or in control cabinets. The following sensors/signal sources can connect over their universal input module:

• (2-wire, 3-wire, 4-wire connection) 2 resistance thermometers
• 2 thermocouples
• 2 linear resistors, potentiometer and DC voltage sources

The output signal is a load-independent direct current from 4 to 20 mA in accordance with the input characteristic, superimposed by the digital HART signal.

The dual input mode also supports drift detection of the inputs, whereby maintenance intervals can be more easily planned.

Transmitters of the "intrinsically safe or Zone 2 increased safety" type of protection can be installed in hazardous areas. The device meets the requirements of the EU Directive 2014/34/EU (ATEX), the FM and CSA regulations as well as other national approvals.

Engineer can configure the SITRANS TR420 via HART. You can carry out the configuration using a handheld communicator or, more conveniently, with a HART modem and the SIMATIC PDM configuration software. Then, the configuration data permanently store in the non-volatile memory (EEPROM).

After correct connection of input and supply voltage, the transmitter outputs a temperature-linear output signal and the diagnostics LED is green. In case of external errors, e.g. sensor short circuit or interruption, the LED flashes red; an internal error is indicated by a permanent red light.

Engineer can connect an ammeter at any time for checking and plausibility via the test terminals. You can read the output current without any interruption, or even without opening the current loop.