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Reference Manual
00809-0100-4021, Rev DA
November 2004
Rosemount 3144P
3-30
HART
a. Select “No” if a sensor is connected to the transmitter
b. Select “Yes” if using a calibration device. By selecting yes, the
transmitter will be put into active calibration mode (see “Active
Calibrator and EMF Compensation” on page 3-31). This is critical if
the calibrator requires constant sensor current for calibration. If
using a calibration device that can accept pulsed current, select “No.
6. Select the appropriate sensor trim units at the ENTER SNSR 1 TRIM
UNITS prompt.
7. Select 1 Lower Only, 2 Upper Only or 3 Lower and Upper at the SELECT
SENSOR TRIM POINTS prompt.
8. Adjust the calibration device to the desired trim value (must be within the
selected sensor limits). If trimming a combined sensor and transmitter
system, expose the sensor to a known temperature and allow the
temperature reading to stabilize. Use a bath, furnace or isothermal block,
measured with a site-standard thermometer, as the known temperature
source.
9. Select OK once the temperature stabilizes.
10. Enter the lower or upper trim point, depending on your selection in
Step 7.
The trim functions should not be confused with the rerange functions.
Although the rerange command matches a sensor input to a 4–20 mA
output—as in conventional calibration—it does not affect the transmitter’s
interpretation of the input.
Dual Sensor Trim
1. Connect the sensor or calibrator device to the transmitter.
a. When using sensors, connect the two sensors or a dual element
sensor
b. When using a calibrator, connect the device to both sensor inputs.
2. Connect the communicator to the transmitter loop.
3. From the Home screen, select 1 Device Setup, 2 Diag/Service,
2 Calibration, 1Sensor Trim, 1 Sensor Inp Trim to prepare to trim the
sensor. Select 1 Sensor 1.
4. The Communicator will prompt the user to select either Sensor 1 or 2.
The sensors can be trimmed in either order, but it is recommended to
trim Sensor 1 first.
NOTE
A warning will appear reminding the user to Set the Control Loop to Manual”
(see “Setting the Loop to Manual” on page 2-2.)
5. The communicator will ask “Are you using an active calibrator?”