Thermo 48i - CO Background Correction

Operation
Calibration Factors Menu
3-20 Model 48i Instruction Manual Thermo Electron Corporation
CO Background Correction The CO Background Correction is determined during zero calibration. The
CO background is the amount of signal read by the analyzer while sampling
zero air. The background signal is the combination of electrical noise and
scattered light. Before the analyzer sets the CO reading to zero, it stores
these value as the CO background correction.
The CO Background screen is used to perform a manual zero calibration of
the instrument. As such, the instrument should sample zero air until stable
readings are obtained. The first line of the display shows the current CO
reading. This reading is the CO background signal. The second line of the
display shows the CO background correction that is stored in memory and
is being used to correct the CO reading. That is, the CO background
correction is subtracted from the CO reading.
XXLO WCONCENTRATIONXXLO W
CO 15.80 PPM
SAMPLE 12:34 ALARMx
CALIBRATION FACTORS:
>BKG 0.000
COEF 1.000
RANGE AVE DIAGS ALARM
XLOW RANGE CONCENTRATION W
CO 15.80 PPM
SAMPLE 12:34 ALARMx
CALIBRATION FACTORS:
>BKG 0.000
LO COEF 1.000
HI COEF 1.000
RANGE AVG DIAGS ALARM