Bronkhorst FlowPlot - Manual (Page 7)

BRONKHORST ®
In realtime mode FlowPlot will ask FlowDDE for actual values at the same interval as the realtime poll time, unless the
sample time is manually set in FlowPlot. By default, the realtime poll time in FlowDDE is 25 ms and normally should
not be changed.
The Graph update time in the Options window in FlowPlot indicates how often FlowPlot will update the graph. Default
this is set to 200 ms, but on fast PCs it may be set lower for smoother plotting.
Setting Short, fast measurement (<=600 s) Long, slow measurement (>600 s)
Fast changes visible Fast changes not visible
FlowDDE Poll time 100 ms (or lower for small systems) 100 ms
FlowDDE Realtime poll time 25 ms 25 ms
Scantime 15 ms 15 ms
Data acquistion time auto 500 ms
Graph update time 200 ms (or lower on fast PCs) 500 ms
The poll times described here are not exact sample times. Therefore, the sample rate is not constant.
It is not necessarily true that FlowDDE will poll for new values exactly once per poll time. Also, the time-
stamp information from the interface will contain a millisecond value at which the data reached it.
For data acquisition and signal processing this is not an ideal situation, since most standard signal
processing functions require a constant sample rate.
2.2 M
AIN WINDOW
The main window is divided into several areas. The graph with all plots is presented in the largest. To the right of the
graph, below the legend, most controls are located.
2.2.1 Basic controls
Three controls are used to control the plot. Start will start acquiring data and plotting the graph and Stop will stop it.
Clear will clear the graph and remove the actual plot lines, but plotting continues from 0.
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