INFICON 3000 Micro GC Gas Analyzer Operating Manual - Manual (Page 150)

7 - 22
PN
07
4-
51
9-
P1
C
3000 Micro GC Operating Manual
7.10.2 Common Integration Events
Frequently used event parameters are explained below. See the 074-538 EZ IQ
Operating Manual for more detailed information.
Figure 7-25 Integration events window
7.10.2.1 Width
The Width event is used to calculate a value for bunching, or smoothing, the data
points before the integration algorithm is applied. Integration works best when
there are 20 points across a peak. If a peak is over sampled (i.e., the sampling
frequency was too high), the Width event will be used to average the data such
that the integration algorithm sees only 20 points across the peak. In setting a
Width value graphically, the narrowest peak in the chromatogram should be used.
A Width event will be applied to a given peak as long as it occurs before or on the
apex of the peak.
The Width event is only used to correct for over-sampling. It cannot correct for data
that was under-sampled (i.e., sampling frequency too low causing fewer than 20
points acquired across the narrowest peak).
NOTE: In most circumstances, an initial Width value based on the narrowest peak
in the chromatogram will be adequate for proper integration of all peaks.
However, a new Width timed event should be entered every time a peak
width doubles.
The Value corresponds to the width in seconds or minutes of a peak. See Figure
7-25 .
7.10.2.2 Threshold
This event is the first derivative, used to allow the integration algorithm to
distinguish the start and stop of peaks from baseline noise and drift. When setting
the Threshold value graphically, a section of baseline must be selected. The
recommended Threshold value is based on the highest first derivative value
determined in that section of the chromatogram.
The Value corresponds to the area, in microvolts, that the software will detect.