RC Systems ST-72, Инструкция по эксплуатации

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ST-72 User's Manual
Document: UM-1007 Revision Level A
5
1.3.2 24 HOUR TREND SCREEN
The ST-72 24 Hour Trend screen shown in Figure 1-3 displays a 24 hour trend of input
data for the channel selected. Vertical tic marks are each hour and horizontal tic marks
are each 10% of full scale. Colored lines indicate alarm levels. The alarm level lines have
triangles on the right end that indicate high and low trip for each alarm level. A triangle
that points up represents a high trip alarm and one that points down represents a low
trip alarm. Since each data point must be collected for several minutes before it may be
displayed, it is likely input values will fluctuate during this interval. Therefore, MAX,
MIN and AVERAGE values are stored in RAM memory for each subinterval. To
accurately portray the trend, a vertical line is drawn between MIN & MAX values for
each subinterval. The AVERAGE value pixel is then left blank, leaving a gap in the
vertical line. This is demonstrated in the
noisy area of the 24 hour trend in Figure 1-3. If
the MAX & MIN values are within 2% of each other there is no need for the vertical line
and only the AVERAGE value pixel is darkened as in the
quiet areas. If there is no trend
data available, the corresponding section of the graph will be grayed out. This will occur
on power interruptions.
The top portion of each trend screen indicates channel number, real time reading in
engineering units, measurement name, range, and MIN, MAX & AVERAGE values for the
preceding 24 hour period. When a channel reaches alarm state, the colored bar
changes to the color that represents that alarm level and flashes. Once the alarm is
acknowledged the bar stops flashing.
Measurement Name 45 ppmH2S
Zero: 0 Span: 100 10/20/2010
Min: 1 MAX: 82 Avg: 26
20Hr 16Hr 12Hr 8Hr 4Hr
100
80
60
40
20
0