Emerson Rosemount 2051G, Reference Manual

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47
Reference Manual
00809-0400-4101, Rev BA
Operation and Maintenance
January 2018
Operation and Maintenance
Calibrate the 4–20 mA output

4–20 mA Output trim ( page 52 )

4–20 mA Output trim using other scale ( page 53 )
5.4.1 Determining necessary sensor trims
Bench calibrations allow for calibrating the instrument for its desired range of operation. Straight
forward connections to pressure source allow for a full calibration at the planned operating points.
Exercising the Transmitter over the desired pressure range allows for verification of the analog output.
“Trim the pressure signal” on page 48 discusses how the trim operations change the calibration. It is
possible to degrade the performance of the transmitter if a trim is done improperly or with inaccurate
equipment. The transmitter can be set back to factory settings using the
“Recall factory trim—
sensor trim” on page 51 .
Determine the necessary trims with the following steps.
1. Apply pressure.
2. Check digital pressure, if the digital pressure does not match the applied pressure, perform a digital
trim. See “Perform a sensor trim” on page 49 .
3. Check reported analog output against the live analog output. If they do not match, perform an
analog output trim. See “Performing digital-to-analog trim (4–20mA output trim)” on page 52 .
Trimming with configuration buttons
Local configuration buttons are external buttons located underneath the top tag of the transmitter.
There are two possible sets of local configuration buttons that can be ordered with the Rosemount
2051G and used to perform trim operations: Digital zero trim and LOI. To access the buttons, loosen
screw and rotate top tag until buttons are visible.

LOI (M4): Can perform both digital Sensor Trim and the 4–20mA Output Trim (analog output trim).
Follow the same procedures listed in trimming with Field Communicator or AMS Device Manager listed
below.

Analog Zero and Span (D4): Used to rerange the transmitter with an applied pressure.

Digital zero trim (DZ): Used for performing a sensor zero trim. See “Determining calibration
frequency” on page 48 for trim instructions.
All configuration changes should be monitored by a display or by measuring the loop output. Figure 5-1
shows the physical differences between the two sets of buttons.
Figure 5-1. Local Configuration Button Options
A. Analog Zero and Span (D4)- green retainer
B. Digital zero trim (DZ)- blue retainer
A
B