Overview; Introduction - Honeywell STT25D Operator's Manual

1.1

Introduction

The STT250 Smart Temperature Transmitter is a microprocessor based unit suitable
for accepting a wide variety of thermocouple and resistance temperature detector
sensor inputs or direct ohm or milli-volt inputs and providing a 2 wire
4-20 mA "Analog", digital "DE", or analog "HART®" proportional output.
The transmitter offers high accuracy and stability together with wide flexibility to suit a
wide range of applications. All adjustments and operational settings are implemented
through the Smart Field Communicator (DE) or the HART communicator (HART).
Both field communicators access the transmitter by connecting across the 4-20 mA
wiring in parallel with the STT250 anywhere along the wiring up to 1500 meters from
the transmitter for both the DE and HART protocol versions.
Note: 1500 m is the maximum HART cable length but may be restricted by cable
capacitance limits.
n
Model STT25H provides the HART protocol output. The terminal assembly is
blue for visible differentiation.
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Model STT25M provides a 4-20mA analog output and is configurable with the
Honeywell Smart Field Communicator (SFC) or the PC based Smartline
Configuration Toolkit (SCT).
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Model STT25D provides both the 4-20mA analog output as in Model STT25M or
the digital DE protocol for digital integration to the Honeywell control system or
other compatible interfaces.
The STT250 is based on a rugged compact package with encapsulated electronics for
high reliability and includes facilities for spring loading of the sensor at a
pitch in accordance with DIN 43729. The unit is available either for DIN rail mounting
or supplied in a variety of enclosures for direct sensor, pipe or wall mounting (See
Figures 6 through 13).
"HART is a Registered Trademark of HART Communication Foundation."
"The STT3000 Smart Temperature Transmitters are manufactured under at least one
of the following patent numbers: 4.734.873, 4.592.002, 4.587.466, 4.553.104,
4.494.183"
Smart Temperature Transmitter STT250 – Operator Manual

1. OVERVIEW

33 mm
1