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Principles of Operation
12.5.10. CALIBRATION - SLOPE AND OFFSET
12.5.11. TEMPERATURE AND PRESSURE COMPENSATION
12.5.12. INTERNAL DATA ACQUISITION SYSTEM (DAS)
238
Teledyne API T802 Paramagnetic O
Two conditions must be simultaneously met to switch to the short filter. First, the
instantaneous concentration must exceed the average in the long filter by a fixed
amount (default setting is <2%). Second, the instantaneous concentration must
exceed the average in the long filter by a portion, or percentage, of the average in
the long filter (also <2%by default).
If necessary, these boxcar lengths as well as the threshold levels can be altered
but with corresponding tradeoffs in rise time and signal-to-noise ratio (contact
Teledyne- API Technical Support for more information).
Calibration of the analyzer is performed exclusively in software.
During instrument calibration the user enters expected values for zero and span
via the front panel keypad and commands the instrument to make readings of
calibrated sample gases for both levels.
linearized, and compared to the expected values. With this information the
software computes values for instrument slope and offset and stores these values
in memory for use in calculating the O
The instrument slope and offset values recorded during the last calibration are
available for viewing from the from the front panel (See Section 3.4.2)
Changes in ambient pressure can have a noticeable effect on the O
CO
concentration calculations. To account for this, the T802 software includes a
2
feature which allows the instrument to compensate both the O
calculations based on changes in ambient pressure. Both sensors are housed
inside temperature controlled manifolds. This minimizes temperature effects on
the measured concentrations.
The DAS is designed to implement predictive diagnostics that stores trending
data for users to anticipate when an instrument will require service. Large
amounts of data can be stored in non-volatile memory and retrieved in plain text
format for further processing with common data analysis programs. The DAS
has a consistent user interface in all Teledyne API analyzers.
parameters and triggering events can be added to the instrument as needed.
Depending on the sampling frequency and the number of data parameters the
DAS can store several months of data, which are retained even when the
instrument is powered off or a new firmware is installed. The DAS permits users
to access the data through the instrument's front panel or the remote interface.
The latter can automatically download stored data for further processing. For
information on using the DAS, refer to Section 7
Analyzer Operation Manual
2
The readings taken are adjusted,
concentration of the sample gas.
2
and optional
2
and optional CO
2
2
New data
07275B DCN6418
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