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13
3.3.3
Steam Measurement
•
Place taps to the side of the line.
•
Mount the transmitter below the taps to ensure that the impulse piping stays
fi
lled with
condensate.
•
In steam service above 250°
F (121°C), fill impulse lines with water to prevent the direct steam
contact with the transmitter and to ensure accurate measurement at start-up.
NOTE
For steam or other higher temperature processes, ensure that the temperature at the
process connection does not exceed the transmitter’s process temperature limits
.
3.4
Field Adjustment
Perform field adjustments only after installing the transmitter at its final work location otherwise the
set parameters may drift due to jerks while transporting or handling.
3.4.1
Zero Point Adjustment
•
For sensor zero trim, ensure that the vessel is empty and there is no input medium
pressure on the diaphragm. The vessel should be applied a normal atmospheric
pressure. If applying external pressure to the transmitter make sure that the display is
sufficiently stabilized (after approximately 10 to 15 seconds), before initiating any trim
function.
•
There are 3 ways of making input pressure “Zero”.
Apply a “Zero” pressure source (mandatory for absolute pressure models).
Apply equal pressure on both HP and LP ports (DP models only).
Open equalizing valve of manifolds installed and venting to atmospheric pressure
(applicable for Gauge & DP type models only).
•
Sensor zero trim can be performed using an external HHC (Handheld calibrator), PC or
PDA configurator, and/or using Zero/Span local push buttons provided on the
transmitter.
•
Using local push buttons set PV=0, refer to section 5.2.1 of this manual for detailed
instructions. If using an external HHT or HART® PC configurator, refer to the user
manual supplied by the third-party supplier.
Flow
