Teledyne GFC-7001T - Trace CO Analyzer - Manual (Page 287)

Troubleshooting and ServiceTeledyne API – Model T300/T300M CO Analyzer
Teledyne Analytical Instruments 287
12.7. FREQUENTLY ASKED QUESTIONS
The following is a list from Teledyne’s Customer Service Department of the most
commonly asked questions relating to the GFC7001T/GFC7001TM CO Analyzer.
QUESTION ANSWER
Why does the ENTR button
sometimes disappear on the Front
Panel Display? During certain types of adjustments or configuration operations, the
ENTR button will disappear if you select a setting that is out of the
allowable range for that parameter (such as trying to set the 24-hour
clock to 25:00:00, or selecting a DAS hold off period of more than 20
minutes).
Once you adjust the setting in question to an allowable value, the ENTR
button will re-appear.
Why is the ZERO or SPAN button
not displayed during calibration? The GFC7001T/GFC7001TM disables these buttons when the expected
span or zero value entered by the users is too different from the gas
concentration actually measured value at the time. This is to prevent
the accidental recalibration of the analyzer to an out-of-range response
curve.
EXAMPLE: The span set point is 40 ppm but gas concentration being
measured is only 5 ppm.
For more information, see Sections 12.3.3 and 12.3.4.
How do I enter or change the value
of my Span Gas? Press the CONC button found under the CAL or CALS buttons of the
main SAMPLE display menus to enter the expected CO span
concentration.
See Section 0 for more information.
Why does the analyzer not
respond to span gas? There could be something wrong with a span gas tank, or a span gas
concentration was entered incorrectly, or there could be a pneumatic
leak. Section 12.3.3 addresses these issues.
Is there an optional midpoint
calibration? There is an optional mid-point linearity adjustment; however, midpoint
adjustment is applicable only to applications where CO measurements
are expected above 100 ppm.
Call Teledyne Customer Service Department for more information on
this topic.
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? This most commonly occurs for one of the following reasons:
 A difference in circuit ground between the analyzer and the data
logger or a wiring problem
 A scale problem with the input to the data logger
(The analog outputs of the GFC7001T/GFC7001TM can be
manually adjusted to compensate for either or both of these effects,
see Section 5.9.3.9).
 The analog outputs are not calibrated, which can happen after a
firmware upgrade
(Both the electronic scale and offset of the analog outputs can be
adjusted; see Section 5.9.3.2. Alternately, use the data logger itself
as the metering device during calibration procedures.