Endress+Hauser Deltabar FMD72, Руководство по эксплуатации

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Deltabar FMD72 Commissioning
45
11.7 Configuring level measurement
11.7.1 Information on level measurement
You have a choice of two methods for calculating the level: "In pressure" and "In
height". The table in the "Overview of level measurement" section that follows
provides you with an overview of these two measuring tasks.
• The limit values are not checked, i.e. the values entered must be appropriate for the sensor
module and the measuring task for the device to be able to measure correctly.
• Customer-specific units are not possible.
• There is no unit conversion.
• The values entered for "Empty Calib./Full Calib.", "Empty Pressure/Full Pressure", "Empty
Height/Full Height", and "Set LRV/Set URV" must be at least 1% apart. The value will be
rejected, and a warning message displayed, if the values are too close together.
11.7.2 Overview of level measurement
Measuring task Level
Selection Measured variable
options Description Measured value display
Calibration is
performed by
entering two
pressure-level value
pairs. "In
pressure" Via the "Unit before lin.
(025)" parameter
(
®
ä
81): %, level,
volume or mass units.
• Calibration with
reference pressure
(wet calibration)
(
®
ä
45)
• Calibration without
reference pressure
(dry calibration)
(
®
ä 47)
The measured value display and
the "Level before lin
(019)"(
®
ä
79) parameter
show the measured value.
Calibration is
performed by
entering the density
and two height-level
value pairs. "In height" • Calibration with
reference pressure
(wet calibration)
(
®
ä 49)
• Calibration without
reference pressure
(dry calibration)
(
®
ä
52)
11.7.3 "In pressure" level selection Calibration with reference pressure
(wet calibration)
Example:
In this example, the level in a tank should be measured in "m". The maximum level is 3 m (9.8 ft).
The pressure range is derived from the level and the density of the medium. In this situation, the
device sets the pressure range to 0 to 300 mbar (4.5 psi).
Prerequisite:
• The measured variable is in direct proportion to the pressure.
• The tank can be filled and emptied.