Startup; Overview; Startup Tasks; Output Check Procedures - Honeywell STT700 SmartLine User Manual

4.1.1. Overview

This section identifies typical startup tasks the STT700 temperature transmitter and includes the
procedure for running an optional analog output check.

4.1.2. Startup Tasks

After completing the installation and configuration tasks for a transmitter, you are ready to startup the
process loop. Startup usually includes:

Setting initial resistance, based on actual temperature (RTD sensor types only)

Reading inputs and outputs

Applying process inputs to the transmitter.
You can also run an optional output check to wring out an analog loop and check out individual
Process Variable (PV) outputs in Digitally Enhanced (DE) mode before startup.
The actual steps in a startup procedure vary based on the type of transmitter and the measurement
application. In general, the procedures in this section are based on using Honeywell MC Toolkit, with
a HART or DE variant, to check the transmitter input and output under static process conditions, and
make adjustments as required initiating full operation with the running process.

4.1.3. Output Check Procedures

The Output Check comprises the following procedures:

The Loop Test procedure checks for continuity and the condition of components in the output
current loop.

The Trim DAC Current procedure calibrates the output of the Digital-to-Analog converter for
minimum (0%) and maximum (100%) values of 4 mA and 20 mA, respectively. This
procedure is used for transmitters operating online in analog mode to ensure proper operation
with associated circuit components (for example, wiring, power supply, control equipment).
Precision test equipment (an ammeter or a voltmeter in parallel with precision resistor) is
required for the Trim DAC Current procedure.

The Apply Values procedure uses actual Process Variable (PV) input levels for calibrating
the range of a transmitter. The PV is carefully adjusted to stable minimum and maximum
levels, and the Lower Range Limit Value (LRV) and Upper Range Limit Value (URV) are
then set by commands from the MC Toolkit.
The transmitter does not measure the given PV input or update the PV output
while it operates in the Output mode.
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4. Startup

STT700 Temperature Transmitter User's Manual
Revision 2