Discrepancy Between Analog Output And Display; Other Performance Problems; Discrepancy Between No And No Slopes; Excessive Noise - Teledyne T200H User Manual

Teledyne API - Model T200H/T200M Operation Manual

7.3.7. DISCREPANCY BETWEEN ANALOG OUTPUT AND DISPLAY

7.3.8. DISCREPANCY BETWEEN NO AND NO

7.4. OTHER PERFORMANCE PROBLEMS

7.4.1. EXCESSIVE NOISE

07270D DCN7141
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.
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 4.13.6.2 for a detailed description of this procedure.
If the slopes for NO and NO
than 1%), consider the following two problems
•
NO impurities in the NO calibration gas. NO gases often exhibit NO
2
of 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
2
values for NO and NO
ppm NO . This problem is worse if NO gas is stored in a cylinder with balance air
X
instead of balance gas nitrogen or large amounts of nitrous oxide (N
oxygen in the 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 5.3 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 5.2.5 for more information
on this feature.
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.
Excessive noise levels under normal operation usually indicate leaks in the sample
supply or the analyzer itself. Make sure that the sample or span gas supply is leak-free
and carry out a detailed leak check as described earlier in this Section.
SLOPES
X
are significantly different after software calibration (more
X
accordingly to different values, e.g., 0.448 ppm NO and 0.45
2
Troubleshooting & Service
. This reaction is
2
2
, increasing over time.
2
in the calibration menu are set to
X
on the order
O). The
2
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