Experimental Physics and
Industrial Control System

"Elder Matias" <[email protected]> · Wed, 21 Oct 2009 07:45:39 -0600

I should have sent this failure report out some time ago in case it is
helpful at one of the other labs.

This summer we had an OMS58 board fail.  The result of the failure was a
less than desirable outcome for one of our Kohzu monocromator.

The nature of the failure is that on several channels this OMS58 board
started sending pulses out to the motors, in complete disregard to any
limit switches and without being commanded by the software.  Without any
hard stops or secondary limit switches that interlock the drive power
the motors continued moving beyond their normal range of travel and did
a bit of damage to the internals of the mono.  In this application we
were relying on the firmware (on the board) to stop the motion when the
limit switches were hit.

We removed the board from the beamline, brought it back to our controls
test lab, were able to reproduce the failure in a different setup.  The
board was shipped back to the supplier, they localized the failure to a
data buffer IC (74245) that is located in U82 on OMS58.

Elder

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System