Honeywell STT171 temperature transmitter

Honeywell STT171 temperature transmitter

Product Overview

The Honeywell STT171 temperature transmitter is a 2-wire programmable device designed for cost-effective and reliable temperature monitoring in industrial environments. As part of the Honeywell STT170 family (economy tier of the STT 3000 series), the STT171 bridges the gap between direct-wired temperature sensors and high-end transmitters, providing improved accuracy, safety, and reliability while reducing cabling costs-1-30. The STT171 converts low-level signals from RTD sensors into a standard 4-20 mA analog current signal capable of long-distance transmission through noisy plant environments-1.

Key Technical Specifications

Sensor Input Capabilities

The Honeywell STT171 accepts a variety of RTD inputs including Pt100 (α=0.00385, α=0.003916), Ni100, Pt1000, and other resistive temperature devices. The STT171 supports 2-wire, 3-wire, and 4-wire RTD connections with automatic cable compensation for 3-wire configurations to ensure measurement accuracy-5. The transmitter is programmed using the STT17C PC-based configuration toolkit, which provides a graphical user interface for easy setup and monitoring of all configuration parameters-1-25.

Output and Communication Features

STT171 delivers a linearized 4-20 mA analog output that is automatically linearized within the user-defined lower and upper range limits-25. The transmitter features programmable high and low alarm limits, with sensor error response compliant with NAMUR NE43 (upscale to 23 mA, downscale to 3.5 mA)-1-25. The STT171 supports sensor failure detection and can be configured to output a user-defined alarm current upon sensor fault.

Safety Certifications

The Honeywell STT171 carries multiple international safety certifications, including:

ATEX: EEx ia IIC T6/T4, KEMA 06ATEX0042 X

FM: Intrinsically safe for Class I, Division 1, Groups A,B,C,D

CSA: Intrinsically safe for Zone 0, Group IIC

IECEx: Certified for hazardous area installations

CE: EMC compliance with EN 61326

For intrinsically safe installations, the STT171 exhibits the following entity parameters: Ui=30 V, Ii=120 mA, Pi=0.84 W, Ci=1 nF, Li=10 µH-5-11. Ambient temperature limits for hazardous area operation are T4: -40°C to +85°C, T6: -40°C to +60°C-5.

Installation and Mounting

The STT171 supports multiple mounting options: direct DIN Form B sensor head mounting, DIN rail mounting (with appropriate housing), or panel mounting. The transmitter can be installed in plastic, aluminum, stainless steel, or carbon steel housings-12. The STT171 must be installed according to National Electrical Code (ANSI-NFPA 70) for hazardous locations, and when mounted in a metal enclosure form B per DIN 43729 with IP6X protection rating, it is suitable for explosive atmospheres caused by combustible dust-33.