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OX-TRAN Model 2/28 Operator's Manual
Introduction
Permeation Test Overview
A "Permeation Test" consists of a series of discrete states that are performed using a Test Cell. The "Cell"
contains a film sample. These states are used to measure the test environment and the transmission rate of
the test sample. A Permeation Test may utilize all or only a subset of the possible test states. During a test,
the steps (or states) within the test are executed in a fixed order. This order is called the "Test Sequence". A
brief description of the states within a permeation test is given below:
Conditioning the Sample
Almost every material requires a period of time to acclimate to the environment and reach equilibrium. A
time period can be specified to allow the barrier to "Condition" to the test environment. The Conditioning
Period when used will occur at the beginning of each test phase.
ReZero State
Periodically the instrument baseline must be measured so that any changes in the baseline will not affect
the accuracy of your transmission rate data. This is done during a "ReZero State" by measuring the
apparent oxygen transmission rate of the ReZero Cell.
Cell Examination State
The Cell Examination State is used to measure the transmission rate of the barrier sample. The carrier gas
leaving the Test Cell is sent to the oxygen sensor where the amount of oxygen contained in the gas is
measured to determine a transmission rate.
Bypass State
When no gas is being routed to the oxygen sensor it is said to be in the Bypass State. The Bypass State is
used to maximize the useful life of the sensor. The oxygen sensor is automatically placed in Bypass during
conditioning, when tests are completed or when an excessively high level of oxygen is detected.
Test Completion
At some point sufficient measurements will have been made to accurately determine the transmission rate
of the samples. A Permeation Test can be terminated manually by the user, after a fixed number of test
cycles or using an automatic convergence process. When testing is complete, the cell is removed from the
test sequence and no further transmission rate examination of that sample is performed. For more
information on stopping a transmission rate test see "Determining When to Stop a Test" in Chapter 3.
Report Generation
You can request a report for one or both cells at any time until a new permeation test is started. See the
instrument Help System for information on printing reports.
MOCON, Inc.
Revision J
1-3
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