Teledyne 9110E - Nitrogen Oxides Analyzer - Manual (Page 206)

Theory of Operation Model 9110E Instruction Manual
192 M9110E Rev B
10.4.4. NO
2
Converter Efficiency Compensation
Over time, the molybdenum in the NO
2
converter oxidizes and looses its original capacity of
converting NO
2
into NO, eventually resulting in a decreased converter efficiency (CE). Even
though we recommend to replace the converter if CE drops below 96%, the analyzer’s
firmware allows adjusting minor deviations of the CE from 1.000 and enables reporting the
true concentrations of NO
2
and NO
X
. Converter efficiency is stored in the instrument’s
memory as a decimal fraction that is multiplied with the NO
2
and NO
X
measurements to
calculate the final concentrations for each. Periodically, this efficiency factor must be
measured and - if it has changed from previous measurements - entered into the analyzer’s
memory (Section 7.1.7). Note that EPA applications do not allow an analyzer to be operated
if efficiency is below 96% or above 102%, even though the analyzer would allow to adjust
for larger discrepancies.
10.4.5. Internal Data Acquisition System (iDAS)
The iDAS 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 iDAS has a consistent user interface among all TAI A-
and E-series instruments. New data parameters and triggering events can be added to the
instrument as needed. Section 6.9.10 describes the iDAS and its default configuration in
detail, Chapter 9 shows the parameters that can be used for predictive diagnostics.
Depending on the sampling frequency and the number of data parameters, the iDAS can
store several months of data, which are retained even when the instrument is powered off.
However, if new firmware or a new iDAS configuration are uploaded to the analyzer, we
recommend retrieving data before doing so to avoid data loss. The iDAS permits users to
access the data through the instrument’s front panel or the remote interface. The latter can
automatically report stored data for further processing. APICOM, a user-friendly remote
control program is the most convenient way to view, retrieve and store iDAS data
(Section 6.11.5).