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Teledyne API - Model 200EH/EM Operation Manual Frequently Asked Questions & Glossary
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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 200EH/EM NO
x
Analyzer.
Q: Why is the ZERO or SPAN key not displayed during calibration?
A: The M200EH/EM 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 80 ppm
and the measurement response is only .5 ppm, 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 doe
s the ENTR key sometimes disappe
ar 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 M200EH reporting range to less than
more than 5000 ppm (200 ppm for a M200EM). 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 options can be automatically calibrated using the instrument’s AutoCal
feature.
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 6.13.4; analog outputs are not calibrated, which can happen after a firmware upgrade (Section
6.13.5).
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.
For the M200EH in its basic configuration, the sample flow should be 290 cm³/min 10%.
For the M200Em in its basic configuration, the sample flow should be 250 cm³/min 10%.
See Table 10-3 for more detailed information bout gas flow rates.
Chapter 11 includes detailed instructions on performing a check of the sample gas flow.
Q: How often do I need to change the particulate filter?
A: On
ce per week. Table 9-1 contains a maintenance schedule listing the most important, regular maintenance
tasks. Highly polluted sample air may require more frequent changes.
Q: How long does the sample pump last?
04521C (DCN5731)