Experimental Physics and
Industrial Control System

Scott Baily <[email protected]> · Thu, 01 May 2014 09:24:01 -0600

On 4/15/2014 6:50 PM, Zenon Szalata wrote:

I have written an EPICS application to move a sensor in a raster
pattern. This is working well. I am stuck though showing the current
raster position using an EDM X-Y graph widget. I have two ai records
which hold the current X and Y position. I thought that I should be able
to use these two scaler PVs for the X and Y graph inputs. The graph
widget displays a symbol at the correct location when the CA connection
is made. However this never gets updated even though the ai X and Y PVs
show continuously changing values. When I take the EDM display into edit
and back to run mode, it shows the symbol in the expected place, but no
further changes. It is as if the X-Y graph widget does not accept
monitors from scaler PVs. Is it possible to achieve what I am trying to
do? Any ideas?
I thought of constructing a waveform record and update it periodically
to simulate the moving raster point. This seems like much work.
Hopefully there is a simpler solution.

This is one of the objects where going through the several screens of

help is very useful. Do you have it set to "plot n pts & stop" instead

of "plot last n pts"? Do you have the update setting for the "trace" set

to "X or Y"? I believe the default is to only plot 2 points and then

stop, and to only update the plot if both X and Y change.

--
Scott Baily
AOT-IC, MS H820
Los Alamos National Laboratory
Los Alamos, NM 87545
ph: (505) 606-2260

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System