Non-Linear Response; Discrepancy Between Analog Output And Display - Teledyne 100E Instruction Manual

Model 100E Instruction Manual
actual gas concentration must be significantly different from the actual zero point (as per
last calibration), which can have several reasons.
• 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 an external zero air
source using SO
need to be replaced (Section 9.3.3).
• Check to make sure that there is no ambient air leaking into the zero air line.
Check for leaks in the pneumatic systems as described in Section 11.5.

11.3.6. Non-Linear Response

The M100E was factory calibrated to a high level of SO
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
fion 11.5.
• The calibration device is in error. Check flow rates and concentrations, particularly
when using low concentrations. If a mass flow calibrator is used and the flow is
less than 10% of the full scale flow on either flow controller, you may need to
purchase lower concentration standards.
• The standard gases may be mislabeled as to type or concentration. Labeled
concentrations may be outside the certified tolerance.
• The sample delivery system may be contaminated. Check for dirt in the sample
lines or sample chamber.
• Calibration gas source may be contaminated.
• Dilution air contains sample or span gas.
• Sample inlet may be contaminated with SO
Verify proper venting of the pump exhaust.
• Span gas overflow is not properly vented and creates a back-pressure on the
sample inlet port. Also, if the span gas is not vented at all and does not supply
enough sample gas, the analyzer may be evacuating the sample line. Make sure to
create and properly vent excess span gas.

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
6.7.4.3. for a detailed description of this procedure.
045150102 Rev XB1
-free air. Check any zero air scrubber for performance. It may
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TROUBLESHOOTING & REPAIR
and should be linear to within
2
exhaust from this or other analyzers.
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