Teledyne GFC-7001E - Trace CO Analyzer - Manual (Page 105)

Basic Operation Model GFC7001E Carbon Dioxide Analyzer
Teledyne Analytical Instruments 105
6.6.4. SETUP  RNGE  UNIT: SETTING THE REPORTING RANGE UNITS
OF MEASURE
The GFC 7001E/EM can display concentrations in parts per million (10 6 mols per mol, PPM) or milligrams per
cubic meter (mg/m 3 , MG). Changing units affects all of the display, COMM port and iDAS values for all reporting
ranges regardless of the analyzer’s range mode. To change the concentration units:
NOTE
In order to avoid a reference temperature bias, the analyzer must be recalibrated after every change in
reporting units.
NOTE
Concentrations displayed in mg/m 3 and ug/m 3 use 0 C@ 760 mmHg for Standard Temperature and
Pressure (STP).
Consult your local regulations for the STP used by your agency.
(Example: US EPA uses 25

C as the reference temperature) .
Once the Units of Measurement have been changed from volumetric (ppb or ppm) to mass units (µg/m 3
or mg/m 3 ) the analyzer MUST be recalibrated, as the “expected span values” previously in effect will no
longer be valid.
Simply entering new expected span values without running the entire calibration routine IS NOT
sufficient.
This will also counteract any discrepancies between STP definitions.