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Cheetah History Mode
By Brian
Ruth
There is an
often requested Cheetah feature for CSC plots to have the ability
to scroll back in time to view things that you may have just
glimpsed as they scrolled off of the screen. It is so
popular, in fact, that we still receive requests for this feature,
even though it has been part of Cheetah for over a year. We
wondered why this feature, which seems to be very desirable, wasn't
being utilized. As it turns out, it isn't being used because
we didn't make it very visible. Only a brief mention in the
Cheetah Reference Guide, and some very subtle display queues, both
contribute to effectively bury this feature. In future
versions of Cheetah, we are going to focus more on making the
popular features more visible and easier to use. For this
tech tip, we will focus on how to use this feature as it exists in
the current version of Cheetah (5.2.1).
We ended up calling this feature History mode, and made it
available for all plots in Time windows. One barrier to
finding out about History mode, is that the words "History
mode" appear nowhere in Cheetah's menus or displays.
History mode is actually a side effect of Freeze Window, which is
another often missed feature. To freeze a window, and thus
enable History mode, you can either just press the spacebar after
selecting the window you want to freeze, or select Freeze Window
from the Time window's Display menu.
Once frozen, the time window will stop updating the traces, and the
title bar of the window will subtly change from:
to:
You can now see
two new items in the title bar after a window is frozen.
First, the word Frozen now appears in the title. Second, to
the right of the word Frozen, a value labeled Start TS is
shown. The Start TS value represents how far into the past
you needed to go to view currently displayed data. This value
is relative to the point where the window was frozen.
Cheetah currently stores the last 30 seconds of data
for each plot in the window.
Once a window is frozen, you can now navigate the data using either
the right or left arrow keys to move either forward or backward in
time, respectively. When paging through the data, the
newest data will always be on the right and oldest on the left of
the window, similar to the Scroll plot mode. All of the
visualization features such as zoom, spread type, window time
adjustment and window resizing work just as they would during live
data display.
After you are finished looking at the historical data, simply
unfreeze the window by pressing the spacebar or selecting the menu
option under the Display menu. The time window will then
return to displaying live data to the screen.
During the time the window is frozen, no new data will be
displayed. This means that you will not be able to page
forward past the point where you froze the window. And, once
unfrozen, you will not be able to freeze the window again to go
back in time and see data that you missed while the window was
initially frozen. Absolutely no data will be
lost. It will still be recorded, and sent to NetCom
applications, but will not be displayed in the window.
History mode is only available on Time windows, and history data is
only saved for plots that are displayed in a window. So, if
you freeze a window and then add a new plot, there will be no historical
data available for the new plot.
If you have any suggestions on how the History mode could be
improved, or any ideas on improving Cheetah, please don't hesitate
to post it to our Cheetah Feature Requests
forum or send an email to support@neuralynx.com .
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