Experimental Physics and
Industrial Control System

john sinclair <[email protected]> · Fri, 10 Dec 1999 11:57:42 -0500 (EST)

On Wed, 8 Dec 1999, Peregrine M. McGehee wrote:

> Here at the Low Energy Demonstration Accelerator we are seeing
> intermittent significant delays in the receipt of CA monitors. As these
> delays are large enough to trigger a hardware protection system that
> places the accelerator in a safe mode (e.g. turn the beam off) we have
> spent considerable time over the past months to understand this.
> 
> We don't yet understand the root cause and are asking if anyone has seen
> a similar effect. We realize that TCP is non-realtime but are concerned
> since these delays can as large as 3 to 10 seconds.

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This came to me right after sending the previous message.

If channel access flow control is the problem, then a seqence number
rather that a 0 to 1 toggle could fix things. The watchdog would get reset
whenever the number changes.

John Sinclair
[email protected]
Oak Ridge National Lab
865-576-6362   865-574-1268 (fax)

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System