Experimental Physics and
Industrial Control System

"Angelic Ebbers" <[email protected]> · Fri, 5 Sep 2008 10:22:10 -1000

Hi,

	I'm seeing this effect on a large variety of records, from
gensub records to some of our custom records (CAD, Apply, taskControl).
I don't see any ca_put_callback delays on these records from the command
line.  I'm increasingly confident that it must be a epics 3.12 to 3.14
compatibility problem.  I've managed to work around the problem by
tweaking the gateway code to attempt to set the channel ready one more
time if it attempts a write and the channel fails a ready check.  It
looks like the initial ready check happens too quickly and some of the
channels are taking longer to set up.  Then it doesn't attempt to set
the channel ready again until an external get is called with "no_cache"
set to true.

Cheers,
Angelic

-----Original Message-----
From: Dirk Zimoch [mailto:[email protected]] 
Sent: Friday, September 05, 2008 2:03 AM
To: Angelic Ebbers
Subject: Re: Gateway problem .... more info

Hi Angelic,

Do you write to one of those records that take a long time to complete a

ca_put_callback? Many SynApps records behave like that. For example the
motor 
record does not become "ready" until motion has finished.

Dirk

Angelic Ebbers wrote:
>>From studying the debugging logs, it looks like some channels
> continuously report:
> "write() pv not ready" when a client tries to write to them through
the
> gateway.
> Then (usually triggered by a caget from a terminal) they become ready
> "vcAdd() connecting -> ready"
> After which a large backlog of writes are allowed through.
> 
> In some cases, I looks like a write to an input field is put on hold
as
> the channel isn't "ready" and then when a write to the Directive field
> goes through, the input field becomes ready and the input is written
> after the directive ... causing the "out of order", and thus failed,
> commands.
> 
> What handshake between the ioc and the gateway is failing to set some
> channels ready while others work properly?
> 
> Some help here would be greatly appreciated.
> Angelic
> 
> 

-- 
Dr. Dirk Zimoch
Paul Scherrer Institut, WBGB/006
5232 Villigen PSI, Switzerland
Phone +41 56 310 5182

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System