Experimental Physics and
Industrial Control System

"Liyu, Andrei" <[email protected]> · Mon, 08 Mar 2004 12:31:30 -0500

	There is another event support from LabView 6.1. There is
occurrence. I used it for CA EpicsToLabView library. Also NI wrote that
LabView 7.0 has normal event support.
	LabView 6.1 is poor in system (OS) area. LabView's strong sides
are math and graphic (not user interface!). It can be used on client
side in big system. On server power of OS, velocity and so on are lost.
LabView has module support but it can be bought separately(?). From
developer view MVC environment is not worse than LabView environment.
	I wrote CA EpicsToLabView library and met next problem. Of
course, I use CA with multithread setting. So each new thread should
connect to CA context. But I don't know when LabView opens new thread
....

Andrei.

-----Original Message-----
From: Brian Tieman [mailto:[email protected]] 
Sent: Monday, March 08, 2004 11:26 AM
To: Ned Arnold
Cc: APS tech-talk
Subject: Re: [Fwd: LabView/EPICS]

Ned,

I've been using the Active-X implementation for a month or two now.  It 
feels more like the Portable Server in that it's easy to create a PV and

have it served without the complications of supporting a full 
record--which is a good thing!  Since most of what I use LabView for is 
quick and dirty, I would be happy with this type of interface as opposed

to full record support.

The biggest problem I have with this Active-X interface and LabView is 
that CA calls queue up.  There's no support for anything like threads or

even events.  The created PV must be in a loop and checked periodically 
to see if a client requests a change.  Also, once a change has been 
detected and the LabView process starts doing its thing, any subsequent 
client requests are ignored until the first request is completed.  The 
client requests seem to be queued in some manner--which can be a real 
problem.

I'm not sure if these issues are inherent to LabView or just my limited 
experience with LabView development, but I have pulled out significant 
clumps of hair over these two issues.

Brian Tieman

Ned Arnold wrote:

>
> I recently had a discussion with the Product Manager of LabView
> Realtime/Embedded about possibly implementing a tightly-coupled EPICS
> interface to LabView. They have heard alot about EPICS from their
> customers and would like to investigate what would be involved in 
> providing this capability in an integrated way.
>
> The first question for us to answer is "what do we want?". So, I would
> like to hear people's experience with the EPICS/LabView interfaces
that
> are currently available. I know of two major ones:
>
>   - Active-X interfaces (for clients and server)
>   - Shared-memory interface to standard EPICS records (3.14)
>
> Please contribute your experiences, comments, ideas, wishes, etc with
> these solutions or let us know of any others that have been done. For 
> those of you familiar with LabView, what other 
> capabilities/features/performance requirements would you like to see?
>
> The goal would be to develop a list of requirements for the
> "out-of-the-box" LabView/EPICS solution.
>
> Please reply by March 12.
>
>
>      Ned
>
>

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System