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Using the Instrument Software
Chapter 5: Permeant Sensor Calibration
You will need to calibrate the system to ensure accuracy in determining water vapor transmission rates.
Calibration also ensures proper automatic compensation in the transmission rates when environmental and
other factors cause the system to drift. Such factors include:
Ambient temperature fluctuation
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•
Excessive vibration from traffic, machines, etc.
To achieve the best possible results, you will need to make sure that your AQUATRAN Model 3/40 remains
properly calibrated. A 100%RH Film Test Cartridge for calibration is provided as part of the Starter Kit (054-
279). You will need to manually calibrate the instrument after one or more of the following conditions occur.
Set up of the system for the first time.
•
Changes of the nitrogen supply tank.
•
Changed the location of the modules.
•
Shut down of the system.
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Suspect your data is not correct.
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Permeant Sensor Accuracy Check
The accuracy of the permeant sensor can only be checked by using a film to generate a reference
transmission rate. The transmission rate of this film must be known to a high degree of accuracy. In
addition, it is highly desirable that the film have NIST traceability. MOCON strongly discourages using any
material that does not meet these conditions.
Mocon strongly advises using only our Certified Films to check the accuracy of the Permeant Sensor. Refer
to the "Permeant Sensor Adjustment Test Setup" in this chapter for information on setting up a test to check
the accuracy of the permeant sensor.
NOTE:
Mocon has available sets of certified NIST traceable films that cover the usual testing range.
A fourth certified NIST traceable film is available for extreme low transmission rate testing.
Call MOCON in the USA for more information at (763) 493-6370.
Performing a Permeant Sensor Calibration
Calibration of the permeant (water vapor) sensor is a two-step process. First, a film sample with a known
transmission rate must be tested. Refer to the "Permeant Sensor Adjustment Test Setup" in this chapter for
information on setting up a film test. The data from the test can then be used to adjust the permeant sensor.
After suitable data is available the "WVTR Calibration" screen can be used to adjust the output of the
Permeant Sensor. Refer to the Instrument Help System for more information on performing a WVTR
Calibration.
After a WVTR Calibration has been made and saved it can be viewed and recalled using the Calibration
History screen. Refer to the Instrument Help System for more information on using the Calibration History
screen.
5-4
AQUATRAN Model 3/40 Operator's Manual
Revision D
MOCON, Inc.
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