Emerson Rosemount 1195 - Sensor Trim; Zero Trim; Full Trim

Rosemount Model 1195/ProPlate/Mass ProPlate
5-18
Sensor Trim
You can trim the sensor using either the full trim or the zero trim
function. The trim functions vary in complexity, and their use is
application-dependent. Both trim functions alter the interpretation
of the input signal.
A zero trim is a single-point adjustment. It is useful for compensating
for mounting position effects, and is most effective when performed
with the flowmeter installed in its final mounting position. Since this
correction maintains the slope of the characterization curve, it should
not be used in place of a full trim over the full sensor range.
When performing a zero trim, ensure that the equalizing valve is open
and all wet legs are filled to the correct levels.
A full trim is a two-point sensor calibration where two end-point
pressures are applied, and all output is linearized between them. You
should always adjust the low trim value first to establish the correct
offset. Adjustment of the high trim value provides a slope correction to
the characterization curve based on the low trim value. The
factory-established characterization curve is not changed by this
procedure. The trim values allow you to optimize performance over
your specified measuring range at the calibration temperature.
Zero Trim
To calibrate the sensor with a HART Communicator using the zero
trim function, perform the following procedure.
1. Vent the flowmeter and attach a communicator to the
measurement loop.
2. From the communicator main menu select 1 Device setup,
2 Diagnostics and service, 3 Calibration, 3 Sensor trim, 1 Zero trim
to prepare to adjust the zero trim.
NOTE
The flowmeter must be within 3% of true zero (zero based) in order
to calibrate using the zero trim function.
3. Follow the commands provided by the communicator to complete
the adjustment of the zero trim.
Full Trim
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To calibrate the sensor with a HART communicator using the full
trim function, perform the following procedure.
1. Assemble and power the entire calibration system including a
flowmeter, HART communicator, power supply, pressure input
source, and readout device (see Figure 5-7).
HART Comm. 1, 2, 3, 3, 1
HART Comm. 1, 2, 3, 3
Model 268 F4, F4, F3, F2,
F1