Discrepancy Between Analog Output And Display; Other Performance Problems; Discrepancy Between No And No Slopes - Teledyne 200E Instruction Manual

Troubleshooting & Repair
• Diffusion of oxygen into Teflon-type tubing over long distances. PTFE or related
materials can act as permeation devices. In fact, the permeable membrane of NO
permeation tubes is made of PTFE. When using very long supply lines (> 1 m)
between high concentrations span gases and the dilution system, oxygen from
ambient air can diffuse into the line and react with NO to form NO
dependent on NO concentration and accelerates with increasing NO concentration,
hence, affects linearity only at high NO levels. Using stainless steel for long span gas
supply lines avoids this problem.

11.3.7. Discrepancy Between Analog Output and Display

If the concentration reported through the analog outputs does not agree with the value
reported on the front panel, you may need to re-calibrate the analog outputs. This becomes
more likely when using a low concentration or low analog output range. Analog outputs
running at 0.1 V full scale should always be calibrated manually. See Section 6.7.3 for a
detailed description of this procedure.
11.3.8. Discrepancy between NO and NO
If the slopes for NO and NO
1%), consider the following two problems
• NO impurities in the NO calibration gas. NO gases often exhibit NO
2
1-2% of the NO value. This will cause differences in the calibration slopes. If the NO
impurity in NO is known, it can easily be accounted for by setting the expected
values for NO and NO
NO . This problem is worse if NO gas is stored in a cylinder with balance air instead
X
of balance gas nitrogen or large amounts of nitrous oxide (N
air slowly reacts with NO to yield NO
• The expected concentrations for NO and NO
different values. If a gas with 100% pure NO is used, this would cause a bias. See
Section 7.2.2 on how to set expected concentration values.
• The converter efficiency parameter has been set to a value not equal to 1.000 even
though the conversion efficiency is 1.0. The actual conversion efficiency needs to
match the parameter set in the CAL menu. See Section 7.1.7 for more information
on this feature.
An instrument calibration with the IZS option (and expected concentrations set to the same
amount) will always yield identical slopes for NO and NO
NO and assumes NO to be the same (with NO
X

11.4. Other Performance Problems

Dynamic problems (i.e. problems which only manifest themselves when the analyzer is
monitoring sample gas) can be the most difficult and time consuming to isolate and resolve.
The following section provides an itemized list of the most common dynamic problems with
recommended troubleshooting checks and corrective actions.
202
are significantly different after software calibration (more than
X
accordingly to different values, e.g., 448 ppb NO and 450 ppb
2
, increasing over time.
2
2
Model 200E Instruction Manual
slopes
X
2
in the calibration menu are set to
X
, as the instrument measures only
X
being zero).
. This reaction is
2
on the order of
2
O). The oxygen in the
044100102 Rev A
2
2