Slope Detection: Supplemental Functions - ABB PGC2000 Operation And Service Manual

higher number causes the system to respond less quickly but is more sensitive. For that reason the
default is set at 8, a median value that provides both good response and sensitivity for most
applications. Peak width only has meaning when slope detect is running.
Slope Detect On tells the method that slope detection will be used for this analysis. It should appear
in the method well before the first peak is expected to start. Slope Detect Off tells the method that
you are finished using slope detection. Slope detection has six commands associated with it use:
On Now
Off Now
Off @ Base
Off @ Valley
Off @ Min
Neg Peak
"On Now" starts slope detection at the next peak. "Off Now" stops slope detection immediately. "Off
@ Base" turns off slope detection at the next baseline condition. "Off @ Valley" turns off slope
detection at the next valley. "Off @ Min" turns off slope detection at the next minimum, whether it is a
baseline or a valley. "Neg Peak" looks for a negative going slope to trigger the slope detection
algorithm. The negative peak search only works for one peak. You must enter another "Neg Peak"
to continue the search for a second negative peak.

Slope Detection: Supplemental Functions

In addition to the basic functions, there are six supplemental slope detection functions which may or
may not be used: peak lumping, tangent skim, baseline definitions, suspend end, end=crest plus,
and area rejection. When and how the method uses them depends on the specific application.
Peak lumping allows you to sum consecutive peaks into a single lumped peak for calculation. It
allows you to focus on the total area of several consecutive components rather than the individual
peak areas. To use peak lumping, turn Peak Lump On prior to the end of the first peak in the series
of peaks to be lumped together (see Figure 4-21). Turn Peak Lump Off after the end of the last peak
in the series. The lumped peak file will include all peaks which end while the lumped peaks function is
active (peaks 2, 3, 4, and 5 in Figure 4-21).
Tangent skim lets you analyze a smaller peak riding on the tail of a large peak. Tangent skim directs
the slope detection algorithm to look for this by identifying a tangent termination point for the next
2000-OSM, F1
2
1
TIME
PEAK LUMP ON
Figure 4-21. EXAMPLE OF PEAK LUMPING
5
3
4
PEAK LUMP OFF
6
4-22