14 GM32 · Technical information · 8011923 · V 1.4 · © SICK AG
Product Description (Details)
Subject to change without notice
2.5.2.4 Determining the zero and reference point
The zero point is determined by creating a zero spectrum by swiveling in a zero point reflec-
tor during the check cycle. This spectrum corresponds to measurement with a measuring
path free from gas.
Based on this zero spectrum and using the device calibration function, the associated
measured concentration values for individual components are determined and output.
A maintenance request is signaled when one of these zero values exceeds a limit value
(normally 2% of the FS).
The absorption measurement deviation determined above is used to calculate the refer-
ence value. The value
is output as reference value for all components.
As described above, there are three causes for reference point drift:
● Wavelength scale drift
● Resolution drift
● Absorption drift
The measures described in
§2.5.2.1 and
§2.5.2.2 keep the first two drift causes within
very strict limits. This is why the value rp gained from absorption measurement is represen-
tative for reference point drift for all measuring components.
2.5.2.5 Monitoring the cell NO filling
The check cycle only runs correctly when the NO cell filling is sufficient.
Determining a value for an NO absorption line serves to monitor the cell concentration.
A maintenance request is signaled when the value sinks below 0.1 absorption units.
rp (70%+[Absorption deviation in %]) FS=
To Next Page
Loading...
Need help?
General
