Calibration Procedures Model GFC7001E Carbon Dioxide Analyzer
Teledyne Analytical Instruments 205
9.6. CALIBRATION OF THE GFC 7001E/EM’S ELECTRONIC SUBSYSTEMS

9.6.1. DARK CALIBRATION TEST

The dark calibration test interrupts the signal path between the IR photo-detector and the remainder of the
sync/demod board circuitry. This allows the instrument to compensate for any voltage levels inherent in the
sync/demod circuitry that might effect the calculation of CO concentration.
Performing this calibration returns two offset voltages, one for CO MEAS and one for CO REF that are
automatically added to the CPU’s calculation routine. The two offset voltages from the last calibration procedure
may be reviewed by the user via the front panel display.
To activate the dark calibration procedure or review the results of a previous calibration, press:
Offset for CO REFsignal
SAMPLE RANGE=50.0 PPM CO= XX.XX
<TST TST> CAL SETUP
SETUP X.X SECONDARY SETUP MENU
COMM VARS DIAG EXIT
SETUP X.X PRIMARY SETUP MENU
CFG DAS RNGEPASS CLK MORE EXIT
DIAG SIGNAL I/O
PREV NEXT ENTR EXIT
SETUP X.X ENTER PASSWORD
818 ENTREXIT
Continue pressing NEXT until ...
DIAG OPTIC DARK CALIBRATION
PREV NEXT ENTR EXIT
DIAG DARK CO DARK CALIBRATION
VIEW CAL EXIT
DIAG DARK REF DARK OFFSET: 0.0mV
EXIT
Offset for CO MEASsignal
DIAG DARK MEAS DARK OFFSET: 0.0mV
EXIT
DIAG DARK DARK CAL 1% COMPLETE
EXIT
DIAG DARK DARK CALIBRATION ABORTED
EXIT
Calibration runs automatically