Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Fri, 21 May 2010 08:59:27 -0500

Ralph,

I thought I saw it on 3.14.11, but I can't reproduce it.  I do get a blank host name the first time I access a PV with an older version of cainfo built with 3.14.8.2.

Mark

________________________________

From: [email protected] on behalf of Ralph Lange
Sent: Fri 5/21/2010 8:31 AM
To: EPICS tech-talk
Subject: Re: Rogue process variables

Whooops, cainfo indeed *does* it.

 > cainfo fred
fred
    State:         connected
    Host:          nsls2rlange.nsls2.bnl.gov:5064
    Access:        read, write
    Data type:     DBR_DOUBLE (native: DBF_DOUBLE)
    Element count: 1

Note, though, that - depending on the performance of network, client and
host machines, and the DNS configuration and status - when Channel
Access does the connection callback, the host name may not be available yet.
cainfo waits for the connection callbacks, then calls ca_host_name() to
get the host name. If Channel Access returns an empty string, cainfo
prints it.

Doing "PV info" from a medm screen does basically the same thing, but
pointing the mouse at the widget and doing the right click leaves enough
time for CA and DNS to have the host name ready when medm wants it.

See https://bugs.launchpad.net/epics-base/+bug/541342 for an explanation
and the fix that was applied to 3.14.10
(Mark, do you still see this on 3.14.10 or later? If so, you probably
should reopen the issue.)

Cheers,
Ralph

On Thu 20 May 2010 20:20:26 Mark Rivers wrote:
> Whoops, cainfo does not do it.
>
> But make an medm screen with a widget for that PV, and then right click
> and select "PV info".
>
> That will give you the name of the IOC machine.
>
> Mark
>
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Mark Rivers
> Sent: Thursday, May 20, 2010 7:16 PM
> To: [email protected]; EPICS tech-talk
> Subject: RE: Rogue process variables
>
> base/bin/linux-x86/cainfo PVName
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of
> [email protected]
> Sent: Thursday, May 20, 2010 7:15 PM
> To: EPICS tech-talk
> Subject: Rogue process variables
>
> Hello all,
>
> I have an IOC running somewhere on the network.
> I can see the PV, but cannot find the ioc process.
> Is there a way from a terminal to find out on which computer/port
> PVs are available?
>
> Thanks,
>
>  

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System