53
Reference Manual
00809-0100-4108, Rev BA
Section 5: Operation and Maintenance
March 2014
Operation and maintenance
Calibrate the sensor
Sensor Trim (
page 56
)
Zero Trim (
page 57
)
Calibrate the 4-20 mA output
4-20 mA/ 1-5V Output Trim (
page 59
)
4-20 mA/ 1-5V Output Trim using other scale (
page 60
)
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 55
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 command in
Recall factory trim—sensor trim on
page 57
.
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 56
.
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/ 1-5 V
output trim) on page 59
.
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 and
used to perform trim operations: Digital Zero Trim and Local Operator Interface. To access the
buttons, loosen screw and rotate top tag until buttons are visible.
Local Operator Interface (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.
Digital Zero Trim (DZ):
Used for performing a sensor zero trim. See
Determining
calibration frequency on page 54
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.
