SITRANS TF320/TF420 – SIL Temp Transmitters

Why SITRANS TF320/TF420?

SITRANS TF320 and TF420 combine flexible sensor connectivity, robust field housing and simple local or remote configuration. Both are available in single- or dual-chamber aluminum or stainless-steel versions. TF320 covers standard measurement points with one universal input. TF420 adds two separately configurable inputs with hot backup for higher availability.

Key benefits

Maximize uptime

Hot backup in SITRANS TF420 automatically switches to a second sensor if the primary fails, helping keep critical processes running and reducing unplanned downtime.

Improve plant safety

SIL 2/3 certification and broad Ex approvals make transmitters suitable for safety‑critical applications and extreme environments down to −50 °C. Optional internal surge protection up to 6kV (dual chamber enclosure).

Adapt to many measurement tasks

With support for RTDs, thermocouples, resistance and mV signals, one transmitter family can be used across a wide range of temperature applications.

Key details

Input	Resistance thermometers, thermocouples, resistors, potentiometers, DC voltage sources
Output	4…20mA (SITRANS TF320), HART 7 (SITRANS TF320/420), Profibus PA (SITRANS TF420)
Material	Aluminum; stainless steel CF3M/1.4409 similar to 316L (dual chamber enclosure); stainless steel 1.4401 similar 316 (single chamber enclosure)
Certificates/approvals	ATEX, IECEx, FM (US/CA), EACEx, NEPSI, KCs, Inmetro, PESO, ECASEx. Protections: Intrinsic safety, increased safety for Zone 2, flameproofed, dust ignition proofed; SIL 2/3; electrical equipment for furnace and ancillary equipment (EN50156-2); marine EURO and DNV
Usability	Hardware and software write protection for maximum security against unauthorized access; uninterruptible loop current measurement for tests; screw terminal wire cross section up to 2.5mm²; internal surge protection up to 6kV (optional)
Accuracy and stability	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 (TF420)