SITRANS TR320/TR420

SITRANS TR320/TR420 are universal, rail-mount temperature transmitters for RTDs and thermocouples, with rich diagnostics and flexible configuration.

Head-mounted temperature transmitters for reliable measurement, easy integration, and advanced diagnostics, from standard to high-availability applications.

Rugged field-mounted temperature transmitters for reliable, accurate measurement, high availability, and plant safety, helping to prevent downtime in SIL 2/3 applications.

The SITRANS TS500’s modular design makes it exceptionally versatile, delivering precise temperature measurements even in harsh industrial environments.

Designed for DIN rail mounting, SITRANS TR320 and TR420 make temperature measurement easier in control cabinets and protective boxes. TR320 covers standard single-input applications. TR420 adds dual-input operation, hot backup and drift detection for higher availability. Universal inputs, HART communication and SIL 2/3 options help standardize instrumentation in demanding plants.

For high-availability applications, TR420 automatically switches to a second sensor if the first fails. Measurement continues without data loss. This helps avoid process interruptions and reduces manual intervention.

One rail-mount platform supports RTD, thermocouple, resistance and voltage inputs. This helps standardize installations, reduce device variants and simplify engineering, spares and operation across many measuring points.

Certified SIL 2/3 variants help meet functional safety requirements in safety-related temperature applications. HART 7 also supports reliable commissioning and testing throughout the device lifecycle.

Resistance thermometers, thermocouples, resistance-type sensors, DC sources

4 … 20mA (SITRANS TR320); HART (SITRANS TR320/420)

Standard: -50 … +85 °C (-58 … +185 °F); SIL: -40 … +80 °C (-40 … +176 °F)

ATEX, IECEx, FM, CSA; EACEx, NEPSI, Inmetro; SIL2/3 (HART only)

Hardware and software write protection for maximum security; uninterruptible loop current measurement for tests; alarm backup via 21mA error current

Top input accuracy for Pt100 (IEC60751) +/- 0.04 °C; Stability: +/-0.05 °C (1 year) or +/-0.18 °C (5 years); 2x 4-wire RTD connection (TR420)

The transmitter can be configured with a handheld device or in SIMATIC PDM for convenient parameterization and diagnostics. Settings are stored in non-volatile EEPROM, so they remain available after power loss or service work.

TR420’s dual-input mode supports sensor drift detection to identify deviation early, plan service proactively and reduce unplanned downtime. It enables hot backup to switch automatically to the second sensor if the first fails.

Galvanic isolation helps maintain signal integrity in demanding environments. A diagnostics bi-color LED provides clear local status information and practical test terminals allow loop current to be verified at any time.

Callendar-van-Dusen-based sensor trim improves accuracy and shortens calibration time. With ambient temperatures down to –50 °C and SIL 2/3 certification for HART variants, it is suited for harsh and safety-related applications.

An integrated LED provides clear local status indication. During normal operation, the LED is green. It flashes red for external faults such as wire break or sensor short circuit, and lights red continuously for an internal device fault. This makes on-site checks faster and easier.

Yes. The HART variants include test terminals for direct loop current measurement without impairing loop integrity. This allows quick current checks during commissioning or service without opening the current loop. In hazardous areas, certified test devices must be used.

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