33
Reference Manual
00809-0100-4825, Rev CB
Section 3: Configuration
March 2014
Configuration
2-Wire RTD offset
The
2-Wire RTD Offset
command allows the user to input the measured lead wire resistance,
which results in the transmitter adjusting its temperature measurement to correct the error
caused by this resistance. Due to a lack of lead wire compensation within the RTD, temperature
measurements made with a 2-wire RTD are often inaccurate. See
resistance effect– RTD input” on page 17
for more information.
To utilize this feature:
1.
Measure the lead wire resistance of both RTD leads after installing the 2-wire RTD and
the Rosemount 248.
2.
From the HOME screen, select 1
Device Setup
,
3 Configuration
,
2 Sensor Configuration, 1
Sensor 1,
2 Snsr 1 Setup,
and
1 2-Wire Offset
.
3.
Enter the total measured resistance of the two RTD leads at the
2-Wire Offset
prompt.
Enter this resistance as a negative (–) value to ensure proper adjustment.The
transmitter adjusts its temperature measurement to correct the error caused by lead
wire resistance.
3.4.7
Information variables
Access the transmitter information variables on-line using the Field Communicator or other
suitable communications device. Following is a list of transmitter information variables which
include device identifiers, factory-set configuration variables, and other information. A
description of each variable, the corresponding fast key sequence, and a review of its purposes
are provided.
Tag
The
Tag
variable is the easiest way to identify and distinguish between transmitters in
multi-transmitter environments. Use it to label transmitters electronically according to the
requirements of the application. The tag defined is automatically displayed when a 375 Field
Communicator establishes contact with the transmitter at power-up. The tag may be up to
eight characters long and has no impact on the primary variable readings of the transmitter.
Date
The
Date
command is a user-defined variable that provides a place to save the date of the last
revision of configuration information. It has no impact on the operation of the transmitter or the
Field Communicator.
Fast Key sequence
1, 3, 2, 1, 2, 1
Fast Key sequence
1, 3, 4, 1
Fast Key sequence
1, 3, 4, 2
