Experimental Physics and
Industrial Control System

Kay-Uwe Kasemir <[email protected]> · Thu, 07 Jul 2005 14:51:32 -0400

On Jul 7, 2005, at 14:26, Andrew Johnson wrote:

Can I get you two to think about these requirements at a slightly

higher level and describe what it is you're trying to achieve, rather

than how we should actually implement it.

Things I had in mind:
- Add a 'maximum' or 'average' to some ai, ao, calc, subroutine, ...
  record instances
- Add a(n additional) forward link to a record
- Make a record post all/some values to a logging facility
  or circular buffer

In case of the max., average, ..., I think it would be really nice
to have this as a field of the record. How else would I access
the current maximum? I'd like to access it via CA, see it in dbpr, ...

I'm all for easing the creation of new record types, so one could create
a new record type that includes this new 'MAX' field.
But I don't want it in every ai, ao, ....,

neither do I like creating an ai, ai_max, ai_avg, ai_max_and_avg, ao,

ao_max, ....

just to cover all permutations, I simply want to add the MAX and/or AGV
field to selected records.
Actually, I don't use the FLNK, HIGH, SIML, ... fields in most records,
so could they all go and only be added as required?

For put logging etc., having a new string field that accepts
some configuration parameter also sounds useful, although not essential.

So I see no basic problem with adding a field at runtime,
only benefits.
We can discuss the details of my proposal:
Only 2 hooks into the process() routine, ... see pro/cons on the wiki.

But then you just suggested _not_ to look at implementation details,

yet ;-)

If I can suggest an alternate approach that could provide this

functionality but doesn't involve "adding a field at runtime", would

you accept this instead?

Absopositively. What do you suggest?

-Kay

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System