8-14 Chapter 8: Calibration
SHB_U14
Postlinearization
Accessories • Zero gas, span gas
• Mix pump or applicable test gas
• PC with TCT
When should
postlinearization be
performed?
• After an IR detector change
• In case of excessive linearity deviation (> 1% of the applicable measurement
range)
• After reconfiguring for other measurement ranges
Note • Optimum postlinearization results are obtained with a test gas and mix pump.
• Since test gases normally have a tolerance of up to 2%, postlinearization with a
test gas will be less precise than postlinearization by mixing with a pump.
• The characteristics of each sample component are determined by parameters a
1
to a
4
. By adapting the two postlinearization parameters, postlinearization provides
for an individual linearity setting.
An initial calibration does not affect these two parameters;
therefore, if postlinearization is impossible after a detector change due to the lack
of a mix pump, these two parameters should be set to 1.
A calibration reset does not affect these two parameters.
• If the large measurement range < 0.15 < c∗l
max
, the postlinearization will calculate
a new linearity function with parameters a
1
und a
2
. (this occurs with very small
measurement ranges)
Parameters a
3
and a
4
are then 0.
The two postlinearization parameters are 1.
Preparation • The IR detectors must be calibrated or have undergone an initial calibration.
• Establish communication with the analyzer module via TCT.
Connect zero or span gas to the sample gas port.
Set the flow rate to the 30-60 l/h range:
Continued on next page
To Next Page
Loading...
