Teledyne T200, Руководство по эксплуатации, Страница: 246 / 425

Troubleshooting & Service Teledyne API
– T200 NO/NO2/NOx Analyzer Operation Manual
244
12.5.4. INABILITY TO SPAN - NO SPAN BUTTON (CALS)
In general, the T200 will not display certain buttons whenever the actual value of a
parameter is outside of the expected range for that parameter. If the calibration menu
does not show a
SPAN button when carrying out a span calibration, the actual
concentration must be outside of the range of the expected span gas concentration,
which can have several reasons.
1. Verify that the expected concentration is set properly to the actual span gas
concentration in the CONC sub-menu.
2. Confirm that the NO
x
span gas source is accurate.

This can be done by comparing the source with another calibrated analyzer, or
by having the NO
x
source verified by an independent traceable photometer.
3. Check for leaks in the pneumatic systems as described in Section 11.3.12.

Leaks can dilute the span gas and, hence, the concentration that the analyzer
measures may fall short of the expected concentration defined in the CONC
sub-menu.
4. If the low-level, hardware calibration has drifted (changed PMT response) or was
accidentally altered by the user, a low-level calibration may be necessary to get the
analyzer back into its proper range of expected values.

One possible indicator of this scenario is a slope or offset value that is outside
of its allowed range (0.7-1.3 for slope, -20 to 150 for offsets). See Section
12.8.4 on how to carry out a low-level hardware calibration.
12.5.5. INABILITY TO ZERO - NO ZERO BUTTON (CALZ)
In general, the T200 will not display certain buttons whenever the actual value of a
parameter is outside of the expected range for that parameter. If the calibration menu
does not show a ZERO button when carrying out a zero calibration, the actual gas
concentration must be significantly different from the actual zero point (as per last
calibration), which may be for any of several reasons.
1. Confirm that there is a good source of zero air. If the IZS option is installed,
compare the zero reading from the IZS zero air source to a zero air source using
NOX-free air. Check any zero air scrubber for performance. It may need to be
replaced (Section 11.3.4.2).
2. Check to ensure that there is no ambient air leaking into zero air line. Check for
leaks in the pneumatic systems as described in Section 11.3.12.
12.5.6. NON-LINEAR RESPONSE
The T200 was factory calibrated to a high level of NO and should be linear to within 1%
of full scale. Common causes for non-linearity are:

Leaks in the pneumatic system:

Leaks can add a constant of ambient air, zero air or span gas to the current
sample gas stream, which may be changing in concentrations as the linearity
test is performed.

Check for leaks as described in Section 11.3.12.

The calibration device is in error:
06858E DCN7057