Re: [EXTERNAL] Re: CA gateway crashes periodically due to badly behaved servers

[Brian Bevins via Tech-talk <tech-talk at aps.anl.gov>]

Thanks, Ralph. It's encouraging to know that the gateway expert doesn't think I'm about to shoot myself in the foot. I'll make a ticket and work on my patches.

I think it should be two separate issues. Keeping the exception handler installed to avoid repeated gateway shutdowns seems straightforward and of general benefit. The gateway vs. Labview issue is much more site specific.

I'll pass on the info about NI's OPC UA. It would certainly make my life easier if the owners would make the problem go away...

Best,

--Brian

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Ralph Lange via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, March 25, 2026 8:59 AM
To: EPICS Tech Talk <tech-talk at aps.anl.gov>
Subject: Re: [EXTERNAL] Re: CA gateway crashes periodically due to badly behaved servers

 

Hi Brian,

As the reluctant Gateway maintainer...

Please create an issue in the upstream ticket system [1], adding the information from this mail. Your workaround / quickfix of keeping the signal handler installed sounds like a reasonable thing to do. Not cancelling the subscriptions after BADMASK also sounds like a feasible option.

On Wed, 25 Mar 2026 at 01:25, Brian Bevins via Tech-talk <tech-talk at aps.anl.gov> wrote:

[...] The Labview PXI crate itself is a complete black box to me. Even the owners know very little about it. The only thing they seem to be able to do with it is configure the environment. The purpose of the gateway for my department is to shield our stuff from this kind of behavior. The frequent disconnections result in a lot of beacon anomalies on our side from the gateway that are kind of playing havoc with systems like our archiver, which is expected to be able to archive PVs from this crate, among others.

Does anybody have any suggestions about how to approach this? At this point I'm ready to hack the gateway to detect the BADMASK and NOT cancel the subscriptions. Only the property info would be lost, and our archiver doesn't care about that anyway. Alternatively, I could patch it to not shut down the VC in response to the Bad ID exception, but that seems riskier.

Pretty much out-of-line, but...

NI offers an OPC UA server that runs on their controllers. For cRIO, we evaluated that and decided it will be our new standard way to integrate cRIO solutions. Don't know about PXI, though.

NI's OPC UA server is certified, thus guaranteed to closely stick to the well-defined protocol. EPICS Integration through the OPC UA support is straightforward.

This would be an investment, doesn't solve your current issues, but might be a simpler long-term solution with less surprises and side-effects.

Cheers,
~Ralph