Experimental Physics and
Industrial Control System

<[email protected]> · Fri, 21 Oct 2011 09:43:38 +0000

If I want to write a new data source for BOY today, can I use org.csstudio.utility.pv in the hope that pvManager will be able to use that as a data source once BOY uses pvManager as a data source? Is DAL still in there?

James

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Carcassi, Gabriele
Sent: 20 October 2011 21:01
To: Kasemir, Kay; [email protected]; [email protected]
Subject: RE: PVManager ReadOnly Check

If you like org.csstudio.utility.pv, then, by all means, use
org.csstudio.utility.pv. Whatever works for you and makes you happy. :-)

Just to clarify: -->as of right now<-- the DataSource class is designed
so that data sources are easy to implement, so that it fits with the
rest of pvManager, *not* so that DataSources are *easy to use*. 

Thanks,
Gabriele

-----Original Message-----
From: Kasemir, Kay [mailto:[email protected]] 
Sent: Thursday, October 20, 2011 3:22 PM
To: Carcassi, Gabriele; [email protected]; [email protected]
Subject: RE: PVManager ReadOnly Check

Hi:

> Something like PV.isWriteAllowed() from org . csstudio . utility . pv 
> would be nice.
I would go even further:
Something like o.c.utility.pv would be nice, period.

The PV manager is great for applications that need to read the average
over the last 10 seconds from N channels, updating at 1 Hz on thread X,
expecting a list of Double, while filtering on only data where ... is
... .
That's really great.
But of course you can't "write" to those PVs because how would you
change the average over the last 10 seconds? Go back 8 seconds and
adjust that original value?

The good news is that the PVManager internally uses a 'DataSource' API
that is similar to utility.pv: It's the raw channel; pluggable
implementations for EPICS V3, simulated channels, then EPICS V4, or
whatever you want to add in the future.

If we allow access to both
a) the DataSource API for those who need/want/prefer a raw channel API
to read and write
b) a PVManager API that can average, queue, schedule update rates,
handle thread access .. I think we'd have it all.

Thanks,
Kay

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System