Unstable Zero And Span; Inability To Span - No Span Button - Teledyne T100 Instruction Manual

Troubleshooting & Repair

Check for disconnected cables to the sensor module.

Carry out an electrical test with the ELECTRICAL TEST procedure in the diagnostics
menu, refer to Section 4.8.6. If this test produces a concentration reading, the analyzer's
electronic signal path is working.

Carry out an optical test using the OPTIC TEST procedure in the diagnostics menu, refer to
Section 4.8.5. If this test results in a concentration signal, then the PMT sensor and the
electronic signal path are operating properly. If the M passes both ETEST and OTEST, the
instrument is capable of detecting light and processing the signal to produce a reading.
Therefore, the problem must be in the pneumatics, optics or the UV lamp/lamp driver.

10.4.3. UNSTABLE ZERO AND SPAN


Check for leaks in the pneumatic systems as described in Section 8.3.6. Consider pneumatic
components in the gas delivery system outside the T100 such as a change in zero air source
(ambient air leaking into zero air line or a worn-out zero air scrubber) or a change in the span
gas concentration due to zero air or ambient air leaking into the span gas line.

Once the instrument passes a leak check, perform a flow check (refer to Section 8.3.7) to
ensure that the instrument is supplied with adequate sample gas.

Confirm the UV lamp, sample pressure and sample temperature readings are correct and
steady.

Verify that the sample filter element is clean and does not need to be replaced.

10.4.4. INABILITY TO SPAN - NO SPAN BUTTON


Verify that the expected concentration is set properly to the actual span gas concentration in
the CONC sub-menu.

Confirm that the SO

If you are using bottle calibration gas and have recently changed bottles, bottle to bottle
variation may be the cause.

Check for leaks in the pneumatic systems as described in Section 10.6.1. 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.

If the physical, low-level 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). Refer to
Section 10.7.2.8 on how to carry out a low-level hardware calibration.
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Leaks in the T100 or in the external gas supply and vacuum systems are the most
common source of unstable and non-repeatable concentration readings.
In general, the T100 will not display certain control 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.
span gas source is accurate.
2
Teledyne ML - T100 UV Fluorescence SO2 Analyzer
06807A(DCNxxxx)