Operation
Calibration Factors Menu
Thermo Fisher Scientific
Model 48
i
Instruction Manual
3-17
●
In the Main Menu, choose
Calibration Factors
.
RESET USER CAL DEFAULTS
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. Before the analyzer sets the CO reading to zero, it stores
this 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.
In the following example, the analyzer is reading 15.80 ppm of CO while
sampling zero air. The CO background correction is 0.0 ppm. That is, the
analyzer is not applying a zero background correction. The question mark
is used as a prompt to change the background correction. In this case the
background correction must be increased to 15.80 ppm in order for the
CO reading to be at 0 ppm.
To set the CO reading in the following example to zero, use
to
increment the CO background correction to 15.80 ppm. As the CO
background correction is increased, the CO concentration is decreased. At
this point, however, no real changes have been made. To escape this screen
without making any changes, press
to return to the Calibration
Factors menu or
to return to the Run screen. Press
to actually
set the CO reading to 0 ppm and store the background correction of 15.80
ppm.
●
In the Main Menu, choose Calibration Factors
>
Bkg
.
CO Background
CALIBRATION FACTORS:
>BKG 0.0
COEF 1.000
O2 BKG 0.0
O2 COEF 1.000
RESET USER CAL DEFAULTS
RANGE AVG DIAGS ALARM
CALIBRATION FACTORS:
>BKG 0.0
LO COEF 1.000
HI COEF 1.000
O2 BKG 0.0
O2 COEF 1.000
RANGE AVG DIAGS ALARM
