Experimental Physics and
Industrial Control System

"Paul Sichta" <[email protected]> · Wed, 16 Feb 2000 15:58:07 -0500

Garrett,
I had a similar problem;  a misbehaving CAMAC link would mess up the mv177
IOC record scan while waiting for a response from the link.  To avoid this I
modified (LANL/CEBAF camacLib.c  revised 03-12-96  by mlr) the 2992 driver
code.  In summary, the link timeout was shortened from about 1 second per
CNAF to about 120 ms for slot-30 write CNAFS,  and to  twice the link
propogation time for non-slot-30 CNAFS.

For a hardware solution, Jorway Corporation makes a Model 176 Serial Byte
Highway Bypass module.  We use these to automatically bypass powered-down
crate-groups to keep the main highway working. Perhaps you can use one of
these to bypass the 750 keV section of the link when the generator is turned
off.

--
Paul Sichta
Princeton Plasma Physics Laboratory
609-243-3477

----- Original Message -----
From: Garrett D. Rinehart <[email protected]>
To: <[email protected]>
Sent: Wednesday, February 16, 2000 3:30 PM
Subject: camac crate init

> I've got a kind of a peculiar Camac here. I'm wondering if any of you
> can help me out.
>
> The Camac is driven by the Hytec 2992 (driver from CEBAF/TJNAF). I'm
> using EPICS_3.13.0b11 on an MV172.
>
> The crate sits in a very nasty (electrically) environment and goes
> "brain-dead" every once in a while. To get around this, I just execute
> the "camacCrateInit" routine from a subroutine record every ten
> seconds. This works very well, generally. Unfortunately, the crate is
> run off a generator ('cus it's in a room that floats at 750keV) and
> it's shut down when the machine is not running. The only problem there
> is that it brings the VME crate to its knees waiting to hear from the
> Camac and, as a result of repeated failed attempts to init the crate,
> eventually crashes. (Note that the mv167 was much more rhobust about
> this than the mv172, but both crash from it.)
>
> My questions to all of you are:
> 1) Is there a better way to do this?
> 2) What is that better way?
>
> Thanks very much in advance.
>
>
> Garrett Rinehart
> Intense Pulsed Neutron Source
> Argonne National Laboratory
> 9700 S. Cass Ave
> Argonne, IL  60439
> (630)252-6561
>
>

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System