Emerson Rosemount 3144P Reference Manual page 62

Rosemount 3144P
3-30
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 3-30). 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.
To trim the second sensor, repeat the same procedure only in Step 4, select
the sensor not yet calibrated (usually Sensor 2)
AMS
For AMS, configure each sensor as indicated above.
Right click on an AI device and select "Diagnostics and Calibration" from
the menu. Select "Calibrate," then "Sensor Trim," then "Sensor Input Trim."
The wizard will continue through the process.
The transmitter may be restored to the factory default by selecting:
"Diagnostics and Calibration," "Sensor Trim," "Revert to Factory Trim."
The wizard will recall the factory trim for a given sensor
Apply changes made (see "AMS" on page 3-5).
Active Calibrator and EMF Compensation
HART Fast Keys 1, 2, 2, 1, 3
The transmitter operates with a pulsating sensor current to allow EMF
compensation and detection of open sensor conditions. Because some
calibration equipment requires a steady sensor current to function properly,
the "Active Calibrator Mode" feature should be used when an Active
Calibrator, which requires a constant sensor current, is connected. Enabling
this mode will temporarily set the transmitter to provide steady sensor current
unless two sensor inputs are configured. Disable this mode before putting the
transmitter back into the process. Disabling this mode will set the transmitter
back to pulsating current. "Active Calibrator Mode" is volatile and will
automatically be disabled when a Master Reset is performed (via HART) or
when power is cycled.
Reference Manual
00809-0100-4021, Rev EA
March 2007