Experimental Physics and
Industrial Control System

Luedeke Andreas <[email protected]> · Tue, 03 Dec 2002 14:02:50 +0100

Maybe tech-talk is a good place to discuss extensions of the VisualDCT.

Currently I'm using the VisualDCT to analyse complex databases.
Those Databases were not written with VisualDCT.
The features required here are:

   * displaying records
   * showing internal interconnections (Links) between the records
   * grouping of the records according to parts of their names
     (it splits the channel name at a predefined character according
     to our naming convention into a "device" and a "property" and
     displays all records of one device in a "group")

These features allow us to analyse databases or templates of dozens or hundreds
of records with rich interconnections. We can use these features because:

   * Grouping is done only by the record names, no extra information is required.
   * We just need to drag the records to appropriate positions to
     get a full view of the information- and process flow in the database
     due to the "rubber band" link display.

We have an (old) "wish list" of what would be nice extensions of VDCT for this purpose:

   * Show links between groups (display a group as a "meta-record")
   * Mark external links with a label "External:" and
   * display external links also in the "group" displays.
   * Provide an "auto-placement" function, that tries to place all records
        + to eliminate the overlap of records
        + to minimize the crossing of links (auto-routing)
   * Visualization of the process chain (an EPICS database simulator)

The implementation of those features would only make sense if a larger
community uses the VisualDCT, since quite some manpower would be needed.

A second purpose for the VisualDCT is to be a programming environment for
EPICS databases. The requirements here are partly different:

   * Syntax checking (already implemented)
   * Handling of substitution files and check of template expansion.
     (All substitution variables provided? Duplicated channels generated?
     Expanded links resolved?...)
   * Tool for database documentation (already many good features provided)

The idea of hierarchical databases falls into this category, too.
I think this should be an "official" extension to the syntax of
databases and templates, too. I.e. dbLoadTemplate should
be extended or replaced to load databases with this syntax.
But even before that, it's a great feature for VisualDCT.

Graphical database configuration is a very basic feature of EPICS.
I guess everyone could add more ideas to the discussion.
Even if we do not have the manpower to implement it :-)

Andreas

Matthias Clausen wrote:

> Grouping and hierarchies would be one of the most important reasons to use VDCT.
> We even need the transparent forwarding of macro substitutions - which is disabled at the moment.
>
> We should collect the requirements for the next release...
>
> Matthias
>
> John Maclean wrote:
>
> > We are drawing up requirements for future versions of VDCT.
> >
> > Based on discussions with a number of people it appears the the grouping
> > facility is not used but is often a source of confusion.
> >
> > So the question is, should we remove grouping from VDCT? If we don't
> > remove it then it will certainly be turned off by default.
> >
> > Note that groups are different from the hierarchy scheme that is now
> > being implemented. See the user manual at
> > http://www.cosylab.com/visualdct/builds/VisualDCT/2.3.1238/doc/MAN-VisualDCT_Users_Manual.html
> > if you need more information on groups or hierarchies.
> >
> > If no one objects we'll remove grouping.
> >
> > John Maclean.

--
Dr. Andreas Luedeke, SLS Operations Manager, Tel:+41-56-3104002
mailto:[email protected], http://people.web.psi.ch/luedeke

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System