Calibration
Multipoint Calibration in Dual/Auto Range Mode
4-8
Model 43i Trace Level-Enhanced Instruction Manual
Thermo Fisher Scientific
sample to zero and from zero to span. This transition time is the time
required to purge the existing air.
▲
Use the following procedure to perform a multipoint calibration in
dual/autorange mode.
1.
If the instrument is equipped with the optional zero/span and sample
valves, connect the zero and span gas to the rear panel bulkheads
labeled ZERO and SPAN, otherwise connect a source of vented zero air
to the SAMPLE bulkhead.
Note
Do not use nitrogen for zero air.
▲
is used to activate the zero and span valves from the run screen.
The lower left-hand corner of the Run screen indicates which mode is
active ZERO, SPAN, or SAMPLE.
2.
To ensure that the zero air is being measured at atmospheric pressure,
check that the zero air flow reported by the analyzer is approximately
0.5 LPM. Actual zero air flow should be 0.8 LPM or more, with the
excess leaving out the atmospheric bypass.
a.
From the Run screen, press
to display the Main Menu.
b.
From the Main Menu choose, Diagnostics >
Flow
to display the
Sample Flow screen.
c.
Make sure that the reported sample flow is less than the actual zero
air flow.
3.
Press
to monitor the zero air reading and wait for the reading to
stabilize.
4.
Press
and choose Calibration >
SO
2
Background
to display the
SO
2
Background screen.
5.
When the reading stabilizes, press
to set the SO
2
reading to zero.
The display flashes the message “SAVING”, and the SO
2
reading is
added to the background correction. Record the stable zero air reading
as Z
SO2
.
6.
Press
to return to the Calibration menu.
