Experimental Physics and
Industrial Control System

Zenon Szalata <[email protected]> · Tue, 15 Apr 2014 17:50:29 -0700

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.

Thanks in advance,
Zen