Experimental Physics and
Industrial Control System

"Jeff Hill" <[email protected]> · Fri, 21 May 2010 14:29:59 -0600

Hi Carl,

I suspect that the gateway has been attached to that PV for a long time, and
that it learned a maximum element count when it initially connected which is
no longer accurate. Rebooting the IOC or restarting the gateway, whichever
is easiest, might help. Also, note that services (a waveform record in an
IOC in this case presumably) generally report a maximum element count when
the client connects, but can choose to return a lesser current amount of
elements later as appropriate. 

PS: I am out the door on the way to Oxford for the codeathon Saturday
afternoon, and since the rules here say that I can't take my smart card out
of country then I will not have email access for some weeks after that, but
perhaps I will see you at the EPICS meeting.

Jeff
______________________________________________________
Jeffrey O. Hill           Email        [email protected]
LANL MS H820              Voice        505 665 1831
Los Alamos NM 87545 USA   FAX          505 665 5107

Message content: TSPA

> -----Original Message-----
> From: [email protected] [mailto:tech-talk-
> [email protected]] On Behalf Of Carl Schumann
> Sent: Friday, May 21, 2010 1:15 PM
> To: [email protected]; Dehong Zhang
> Cc: Salah J Chaurize; Denise S. Finstrom
> Subject: PV's element count differs though CA gateway
> 
> Tech-talk, Dehong Zhang,
> 
> We have a client application which attempts to access a PV's elements 0
> to 999 .   This application is run on two sets of machines.   One set
> must go through an EPICS gateway to access the PV.  The other set does
> not do so.    The application does not run properly when going through
> the gateway because of an out-of-bounds error at element 940.   It is
> able to access elements all they way up to 999 without issue when there
> is no gateway involved.
> 
> We were able to track this issue down to a difference in the element
> count reported by the originating IOC vs. the gateway using cainfo.
> For the gateway case cainfo reports element count 940, but for the
> non-gateway case cainfo reports 1000.    Using EPICS_CA_ADDR_LIST we
> were able to reproduce both element counts on a single machine depending
> on whether the gateway or the originating IOC responded.   The result is
> attached.
> 
> Me and my co-workers find this result unexpected and are not sure how to
> fix it.   Any help would be appreciated please.  Thanks for your time.
> 
> Sincerely,
> Carl Schumann
> 
> P.S.: for my co-worker Dehong owner of the hins_ws.py:
> The client is hins_ws.py.   The PV is PD_LEBT:Inst:WS1.RST1.   It is the
> out-of-bound error that prevents the Save Result button from generating
> a file.   Do have any insight about what might be going on here?  Thanks.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System