Teledyne 9110EH - Nitrogen Oxides Analyzer - Manual (Page 45)

Model 9110EH Instruction Manual Frequently Asked Questions & Glossary
4. FREQUENTLY ASKED QUESTIONS &
GLOSSARY
4.1. Frequently Asked Questions
The following list contains some of the most commonly asked questions relating to the
Model 9110EH NO
x
Analyzer.
Q: Why is the ZERO or SPAN key not displayed during calibration?
A: The M9110EH disables certain keys whenever the chosen value is out of range for that
particular parameter. In this case, the expected span or zero value is too different from the
actually measured value and the instrument does not allow to span or zero to that point. If,
for example, the span set point is 400 ppb and the measurement response is only 50 ppb,
the SPAN button will not appear to prevent the user from spanning to an out-of-range
response curve. Chapter 11 describes this in detail.
Q: Why does the ENTR key sometimes disappear on the front panel display?
A: Sometimes the ENTR key will disappear if you select a setting that is invalid or out of
the allowable range for that parameter, such as trying to set the 24-hour clock to 25:00:00
or a range to less than 10 or more than 20000 ppb. Once you adjust the setting to an
allowable value, the ENTR key will re-appear.
Q: Why does the analyzer not respond to span gas?
A: There are several reasons why this can happen. Section 11.3.2 has some possible
answers to this question.
Q: Can I automate the calibration of my analyzer?
A: Any analyzer with zero/span valve or IZS option can be automatically calibrated using
the instrument’s AutoCal feature.
Q: Can I use the IZS option to calibrate the analyzer?
A: Yes. However, the accuracy of the IZS option’s permeation tube is only ±5%. Whereas
this may be acceptable for basic calibration checks, the IZS option is not permitted as a
calibration source in applications following US EPA protocols. To achieve highest accuracy, it
is recommended to use cylinders of calibrated span gases in combination with a zero air
source. TAI offers a zero air generator Model 701 and a gas dilution calibrator Model 700
for this purpose.
Q: What do I do if the concentration on the instrument's front panel display does not match
the value recorded or displayed on my data logger even if both instruments are properly
calibrated?
A: This most commonly occurs for one of the following reasons: (1) a difference in circuit
ground between the analyzer and the data logger or a wiring problem; (2) a scale problem
with the input to the data logger. The analog outputs of the analyzer can be manually
calibrated to compensate for either or both of these effects, see Section 6.7; analog outputs
are not calibrated, which can happen after a firmware upgrade (Section 6.7.3.2).
Q: How do I measure the sample flow?
A: Sample flow is measured by attaching a calibrated flow meter to the sample inlet port
when the instrument is operating. The sample flow should be 500 cm³/min ±10%.
Chapter 11 includes detailed instructions on performing a check of the sample gas flow.
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