Rosemount TankRadar Rex DAU 2100, Руководство по обслуживанию

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5-3
Rosemount Tank Radar Rex
Chapter 5 Calibration
Service Manual
308012En, Ed.2
May 2013
5.3 Using the WinSetup Calibrate function
The Calibration function is a tool to adjust the RTG in order to minimize
the offset between actual (hand dipped) product levels and the
corresponding values measured by the transmitter. By using the
Calibrate function you can optimize measurement performance over the
whole measurement range from the top to the bottom of the tank.
The Calibration function calculates a new Calibration Distance based on
fitting a straight line to the deviations between hand dipped levels and
levels measured by the transmitter.
For the 3950 still pipe gauge the calibration function is specially suitable
since a minor adjustment of the Scale Factor is often necessary. The
radar propagation velocity is dependent on the inner diameter of the still
pipe, and the Scale Factor parameter is used to adjust the transmitter to
take this effect into account. Since the average diameter is often difficult
to determine accurately a calibration is often needed.
Procedure
The adjustment process includes the following steps:
1 Recording the hand dipped ullage values and the corresponding
RTG level values.
2 Entering the hand dipped levels and the RTG level values into
WinSetup.
3 Inspect the resulting calibration graph and, if necessary, exclude
measurement points which should not be used in the adjustment
calculation.
5.3.1 Required information
Make sure that the following information is available when you intend to
use the
RTG Adjustment function in TankMaster WinSetup:
• A list of hand dipped ullage values.
• A list of RTG level values corresponding to the hand dipped
ullage/level values.