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long it will take to fill the memory, at the current chart speed, before the data will start to be
recycled.
There are three separate "queues" of data, represented by the three different chart speeds.
As you zoom in and out it switches between these different "queues".
These "queues" are not all the same length, so for example:
The result of this is that the slow speed will tend to give you much more elapsed time history,
but at a lower time resolution, here is a representation of what this could look like.
The lines represent absolute time coverage. So if you go right back to the earliest time on
the slowest chart (shown by '!' in this example), you cannot zoom in any more as the medium
speed coverage does not go back that far.
The example in
full zoom in/zoom out capabilities. When the screen is switched to replay the chart speed is
set to Fast (600mm/hr) and the replay screen displays a 4 hour chart. The replay chart can
be zoomed out two more times to 10 hours, then to 12 hours. It can be zoomed in from 4
hours to 2hrs, 1hr, 1hr (with bigger divisions), 10 mins, 5 mins, 2 mins and 1 min. The Me-
dium chart speed (20mm/hr and the Slow chart speed (5mm/hr) are also shown in the ex-
ample.
160
See "Storage Bias" on page 102
How Replay works
• The fast speed may be at 600mm/hr which means to cover 24 hours takes approx.
30Mbytes for 8 pens.
• The medium speed may be at 20mm/hr which means that to cover 24 hours takes 1Mbyte
(1/30 of fast ).
• The Slow speed may be at 1mm/hr which means that to cover 24 hours takes 50Kbyte
(1/20 of Medium).
2 week
4 weeks
Fast speed
Zooming Capabilities
Figure 6.4 on page 161,
Data
6 weeks
8 weeks
Medium speed
!
shows 10 different replay screens covering the
12 weeks
Slow speed
43-TV-25-35 GLO Iss.4 Dec 06 UK
A5E01001767-04
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