Re: CLS OMS 58 Failure Report

[Ron Sluiter <sluiter@aps.anl.gov>]

Hello Elder,

This failure, and the vendor's fix, are documented in the following 
tech-talk message;
http://www.aps.anl.gov/epics/tech-talk/2006/msg01261.php

From the above message;
> OMS VME58 user's should review what the consequences of
> having this failure occur at their facilities would be.
> The decision to have your boards retrofitted should strike
> a balance between the probability of board failure (higher
> if exposed to radiation) and the consequences of that
> failure. 
Ron

Elder Matias wrote:
> 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
>
>