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<== Date ==> <== Thread ==>

Subject: RE: dm and edm problems with CA gateway
From: "Jeff Hill" <[email protected]>
To: "'Ralph Lange'" <[email protected]>, "'Rolf Keitel'" <[email protected]>
Cc: "'tech_talk'" <[email protected]>
Date: Fri, 4 Mar 2005 16:38:09 -0700
Ralph,

> I was already reporting this problem some months ago

I dont see an entry in Mantis for this so I took the liberty of
creating one.

Jeff

> -----Original Message-----
> From: Ralph Lange [mailto:[email protected]] 
> Sent: Friday, March 04, 2005 3:34 PM
> To: Rolf Keitel
> Cc: tech_talk
> Subject: Re: dm and edm problems with CA gateway
> 
> 
> Hi Rolf,
> 
> we have seen the same problems with the V2.0 Gateway running 
> on Linux. I 
> was able to cut it down to a small Linux system with just one
analog 
> record running on a soft IOC and a Gateway running on the 
> same machine 
> exporting this channel on a different port number. Starting 
> camonitor on 
> a different host to directly watch the channel on the IOC I 
> was able to 
> see random junk values being written into the channel as soon
as two 
> clients are writing fast (slider) through the Gateway. Not just
jumps 
> (that I'd expect), but really random bit patterns that are 
> interpreted 
> as doubles. No matter which system the clients run on (tested
with HP 
> and Linux). Connecting the clients directly to the soft IOC - 
> no problem.
> 
> At BESSY it didn't kill hardware as our DRVHs are set properly
... I 
> hope. We lost the beam a couple of times until - as an 
> instant measure - 
> we stopped running write accesses through the Gateway. Read
accesses 
> seem to work fine.
> 
> The V1 Gateway does not show this behaviour - but we had to 
> switch to V2 
> because the old hardware died.
> 
> I was already reporting this problem some months ago, but the
APS 
> installation hardly uses write access through the Gateway (if 
> at all), 
> so Ken doesn't see these problems - which makes it hard 
> finding the bugs 
> as well as the motivation to fix them. But again: One Linux 
> box running 
> one ao channel on a soft IOC, the Gateway, the camonitor, and 
> two simple 
> clients is enough to reproduce the problem. (On my RH8 Linux 
> box, at least.)
> 
> Hope this helps (well, I know it doesn't really, but ...;-)
> Ralph
> 
> 
> Rolf Keitel wrote:
> 
> > **** Has anybody else experienced these problems? ****
> >
> > When we are operating sliders to write process variables 
> through the 
> > CA gateway, every now and then on releasing the sliders the
gateway 
> > writes huge (and I mean   r e a l l y   huge positive or
negative) 
> > numbers to the IOC, which set the PV to the upper or lower 
> end of the 
> > allowed range.
> > This never happens if you don't use the gateway.
> >
> > We observed this behaviour both with dm and with edm (running
on 
> > Solaris or Linux Redhat 9).
> > The gateway is running on a Linux (Redhat 9) box. Several
gateway 
> > releases up to Beta18 (built against EPICS R3.14.6) exhibit
this 
> > behaviour.
> >
> > We lost a couple of devices, where a user hadn't specified a
proper 
> > DRVH for the setpoint.
> > We have taken the gateway out of operation until this is
resolved.
> >
> > - rolf -
> >
> 



References:
Re: dm and edm problems with CA gateway Ralph Lange

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