RE: lvDCOM (LabVIEW -> EPICS PVs on Windows)

[<freddie.akeroyd@stfc.ac.uk>]

Hi Emmanuel,

 

there are a couple of scripts in the distribution kit that will give you starting points for both the XML file and associated EPICS DB file. The scripts grab everything on the front panel and generate both “input” and “output” records (they can’t distinguish controls from indicators) so afterwards you just need to edit the files and delete the entries that are not appropriate. The first part of this process, however, currently requires access to a copy of LabVIEW to interactively run the “Export Strings” wizard – if this is not practical for you (e.g. you only have compiled LabVIEW applications, or many VIs) let me know and I’ll write a small utility to do this (the LabVIEW  ExportVIStrings() method is accessible via DCOM).

 

The other caveat that I should mention is lvDCOM only works with controls/indicators that are either simple types or arrays of such types i.e. accessing items embedded in LabVIEW clusters is currently not supported. While it is possible to access clusters via DCOM, you have to read/write the cluster as a whole unit which may not be ideal depending on the situation, but cluster access is a feature that I could add if it would be useful.    

 

Regards,

 

Freddie

 

 

From: Emmanuel Mayssat [mailto:emayssat@outlook.com]
Sent: 03 October 2013 21:06
To: Akeroyd, Freddie (STFC,RAL,ISIS); tech-talk@aps.anl.gov
Subject: RE: lvDCOM (LabVIEW -> EPICS PVs on Windows)

 

"lvDCOM allows LabVIEW variables to be accessed by EPICS aware tools,"
Interesting....

can the XML file (Labview variable to asyn variable) be generated automatically (or semi automatically)?
--
Emmanuel

> From: freddie.akeroyd@stfc.ac.uk
> To: tech-talk@aps.anl.gov
> Subject: lvDCOM (LabVIEW -> EPICS PVs on Windows)
> Date: Thu, 3 Oct 2013 18:46:31 +0000
>
> lvDCOM is an EPICS support module that can export front panel variables from National Instruments LabVIEW software applications as EPICS process variables on computers running the Microsoft Windows operating system. The program allows you to rapidly "EPICS enable" existing LabVIEW applications as it is not necessary to modify Virtual Instrument (VI) internals, so it could be used to conveniently wrap e.g. manufacturer supplied applications. As the program uses DCOM for communication, this (ActiveX) needs to be selected in the "VI Server" options of LabVIEW, but this is the only required change to a VI.
>
> Features of lvDCOM include:
> * Able to communicate with either native LabVIEW VIs or compiled LabVIEW applications (.EXE)
> * Can (optionally) automatically start and/or stop VIs on IOC startup/shutdown
> * Can communicate with remote Windows PCs using standard DCOM authentication or a supplied username + password
> * Can handle some additional front panel logic e.g. automatically push a front panel button either before doing a read from, of after doing a write to, another front panel variable
>
> For more information on lvDCOM see http://epics.isis.stfc.ac.uk/
>
> Regards,
>
> Freddie Akeroyd
> --
> Scanned by iCritical.
>

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