Experimental Physics and
Industrial Control System

Bill Brown <[email protected]> · Wed, 14 Apr 1999 10:20:26 -0700

We have an upcomming project that requires a field bus.  We're
seriously considering CAN bus, which looks like a good fit from
a systems point of view.

One of the requirements is that we generate a spec for the vendor
in the very near future.  Are there COTS CAN Bus devices (a/d, d/a,
binary i/o) that the vendor could integrate into his product which
would make our specification a little more "bullet-proof?"

We don't want to ask a vendor to invent his own CAN Bus device for
this project; that seems like a sure way to cause a lot of grief.

We would really like the interface to be at the digital rather than
the analog level.

Any pointers/suggestions would be greatly appreciated.  

-- 

-bill

p.s.  We've got the i/o going in our compactPCI chassis running
EPICS R3.12.b12, using "out of the box" drvIpac stuff and a home-
grown (groan?) driver layer for the cPCI-200 IP carrier.  We'll 
use the same approach for the mentioned project, hopefully with
the existing CAN Bus controller support in EPICS.

The only really ugly part of the whole thing is having to add some
conditionally compiled lines to take care of the byte-swapping
required to go from big-endian (PPC) to little-endian (cPCI).

OTOH, the current project does not require the use of interrupts,
so that feature remains to be implimented.

These changes are confined to the IP pack driver and to drvIpac.c

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System