EPICS interface for CompactRIO?

[Richard2950]

Does anyone know if there is an EPICS (Experimental Physics Instrument Control System) interface library available that would allow a CompactRIO system to directly post data to an EPICS server? I know there are libraries for regular LabVIEW that do this, but I haven't heard of one for CompactRIO.

[Tunde_A]

Hi Richard,

Need more information about your setup. What kind of EPICS server are you using ?

Tunde 

[Richard2950]

I don't know the details, I just know there are LabVIEW Channel Access vi libraries that allow you to read and write EPICS data. The question is whether  these will work on an RT platform. I think the answer is no, but I am hoping to be proven wrong!

[Tunde_A]

Hi Richard,

Where can I find this "Channel Access libraries" ?

Tunde.

[Richard2950]

Here are sources for some LabVIEW-to-EPICS libraries

http://www.sns.gov/diagnostics/documents/epics/LabVIEW/SNS_LabVIEWEPICS.html#Top

http://www.sns.gov/diagnostics/documents/epics/Downloads/downloads.html

http://lansce.lanl.gov/EPICSdata/epics.htm

http://lansce.lanl.gov/EPICSdata/ActiveXCAServer/default.htm

[pppl]

Besides the various LV interfaces available from the EPICS community, NI has released a Channel Access (EPICS) network protocol interface which runs under the Data Supervisory & Control add-on.  It was demo'd by NI at our facility...seemed to work.  I've got a demo now so will look further.

[Jenifer]

As pppl mentioned,  NI is working on a piece of software that will allow a LabVIEW Windows application to be an EPICS client. This is implemented as a plug-in for the LabVIEW shared variable. The plug-in allows a LabVIEW for Windows application to read and write variables on the network using EPICS Channel Access Protocol. At this point, we cannot host an EPICS database - just be a client in the system. We are calling this the LabVIEW EPICS Client I/O Server ("I/O Server" is the LabVIEW name for these types of plug-ins).

Using LabVIEW shared variables, you can get a LabVIEW Real-Time node (i.e. CompactRIO system) to participate in the EPICS system; however, it will need to communicate through a LabVIEW Windows node. You can think of the LabVIEW Windows node as "translating" channel access protocol to LabVIEW shared variable protocol. The attached powerpoint file gives you a visual of how this works (slide 8).

The LabVIEW EPICS Client I/O Server requires LabVIEW and LabVIEW DSC (Datalogging and Supervisory Control) Module, version 8.0 or 8.20.

Regards,

Jenifer Loy

Product Strategy, LabVIEW Real-Time

National Instruments

[Vasilich2004]

Jenifer hi,

Your presentation has small discrepancies.

1. At the beginning, a sequencer does connect to Epics DB directly. But currently the sequencer connects through Channel Access (CA) protocol.

2. On your pictures any CA can't access to data on LV computer. That is important.

There is another way. LV client can write data into normal Epics server. Then any CA client can access to data. Unfortunately, you can't transfer timestamp by CA writing operation and timestamp will not be correct