No Response; Unstable Zero And Span - Teledyne T200 Operation Manual

Teledyne API – T200 NO/NO

12.5.2. NO RESPONSE

12.5.3. UNSTABLE ZERO AND SPAN

06858E DCN7057
/NO Analyzer Operation Manual
2 X
If the instrument shows no response (display value is near zero) even though sample gas
is supplied properly and the instrument seems to perform correctly.
1. Carry out an electrical test with the ELECTRICAL TEST procedure in the
diagnostics menu, see Section 12.7.12.2.

If this test produces a concentration reading, the analyzer's electronic signal
path is correct.
2. Carry out an optical test using the OPTIC TEST procedure in the diagnostics menu,
see Section 12.7.12.1.

If this test results in a concentration signal, then the PMT sensor and the
electronic signal path are operating properly.

If the T200 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 or the ozone generator.
3. Check if the ozone generator is turned on.

Usually, the analyzer issues a warning whenever the ozone generator is turned
off.

Go to SETUP-MORE-DIAG-ENTR, then scroll to the OZONE GEN OVERRIDE
and see if it shows ON.
If it shows OFF, turn it ON and EXIT the DIAG menu.

If this is done and the ozone flow is correct, the analyzer should be properly

supplied with ozone unless the generator itself is broken.
4. Confirm the lack of response by supplying NO or NO2 span gas of about 80% of the
range value to the analyzer.
5. Check the sample flow and ozone flow rates for proper values.
6. Check for disconnected cables to the sensor module.
7. If NO signal is zero while NO signal is correct, check the NO/NOx valve and the
2
NO converter for proper operation.
2
Leaks in the T200 or in the external gas supply and vacuum systems are the most
common source of unstable and non-repeatable concentration readings.
1. Check for leaks in the pneumatic systems as described in Section 11.3.12.
2. Consider pneumatic components in the gas delivery system outside the T200 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.
3. Once the instrument passes a leak check, do a flow check (this chapter) to ensure
that the instrument is supplied with adequate sample and ozone air.
4. Confirm the sample pressure, sample temperature, and sample flow readings are
correct and steady.
5. Verify that the sample filter element is clean and does not need to be replaced.
Troubleshooting & Service
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