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Calibration
Calibration in Dual Range and Auto Range Mode
Calibration in Dual
Range and Auto
Range Mode
Set NO and NO
Background to Zero
4-16
42iQHL Instruction Manual
The dual/auto range calibration feature is used to calibrate the analyzer at
two different span levels (as opposed to a single span level in the standard
mode) generating a "tailored multi-point" calibration curve stored in the
analyzer's memory. This feature may be used:
When widely different gas levels are being monitored, such as a factor
●
of 10 or greater apart
If precision and span levels are being introduced using separate tanks
●
If more than one multi-component cylinder is being used to calibrate
●
the instrument
Properly designed chemiluminescence analyzers are inherently linear over a
wide dynamic range; and under normal U.S. EPA compliance situations
this feature is not required. Dual calibration may be used for span levels less
than a factor of 10 apart, however if this is done to correct for a significant
non-linearity, it may mask the problems causing the effect, such as, bad
calibration cylinder, leaks in sampling lines, or low ozonator output.
Use the following procedure to set the NO and NO
x
Both the NO and NO
For detailed information about the menu parameters and the icons used in
these procedures, see the "Operation" chapter.
1. Follow the "Pre-Calibration" procedure described previously in this
chapter.
2. Be sure the instrument is in the auto or dual mode. If the instrument is
not in auto or dual mode:
a. From the Home screen choose Settings>Measurement
Settings>Range Mode Selection.
b. Select Auto or Dual mode.
3. Introduce zero air to the SAMPLE bulkhead and allow the analyzer to
sample zero air until the NO, NO
4. After the responses have stabilized, from the Home Screen, choose
Calibration>Calibrate Backgrounds>Calibrate NO Background.
background screens operate the same way.
x
, and NO
2
backgrounds to zero.
x
responses stabilize.
x
Thermo Scientific
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