7 Trim the transmitter
Devices are calibrated by the factory. Once installed, it is recommended to
perform a zero trim on gage and absolute transmitters to eliminate error
due to mounting position or static pressure effects. A zero trim can be
performed using either a Field Communicator or configuration buttons.
For instructions using AMS Device Manager, see the Rosemount
™
2051
Reference Manual.
Note
When performing a zero trim, ensure the equalization valve is open and all
wet legs are filled to the correct level.
CAUTION
It is not recommended to zero an absolute transmitter
Procedure
Select trim procedure.
a) Analog Zero Trim – Sets the analog output to 4 mA.
• Also referred to as a “rerange,” it sets the Lower Range Value
(LRV) equal to the measured pressure.
• The display and digital HART output remains unchanged.
b) Digital Zero Trim – Recalibrates the sensor zero.
• The LRV is unaffected. The pressure value will be zero (on display
and HART output). 4 mA point may not be at zero.
• This requires that the factory calibrated zero pressure is within a
range of three percent of the URV [0 ± 3% x URV].
7.1
Example
URV = 150 psi
Applied Zero Pressure = + 0.03 x 150 psi = + 4.5 psi (compared to factory
settings) values outside this range will be rejected by the transmitter
7.2
Trimming with a Field Communicator
Procedure
1. Connect the Field Communicator, see Connect the wiring and power
up for instructions.
May 2019 Quick Start Guide
Quick Start Guide 19
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