Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Mon, 13 Nov 2006 15:45:28 -0600

The transition cards that the APS BCDA group built to connect the
OMS58/MAXv and the ACS Step-Pak drivers have on-board de-glitching
capacitors.  These increase the time constant on the limit switch lines
so that we never see problems, even with very long lines from the
controller to the driver.

This is generally a simple and cheap solution.

Mark

> -----Original Message-----
> From: Ronald L. Sluiter [mailto:[email protected]] 
> Sent: Monday, November 13, 2006 2:15 PM
> To: Emmanuel Mayssat
> Cc: EPICS
> Subject: Re: Motion control failure at APS
> 
> The OMS VME58 is susceptible to noise on the limit switch lines.
> This has been the most frequent problem that I have been called on
> the diagnose.
> 
> Kurt Goetze and I did some testing to see if this is a 
> problem with the
> MAXv.  Of course we can't quantify it, but it appears that OMS has
> done a much better job with the MAXv on this issue.
> 
> Ron
> 
> Emmanuel Mayssat wrote:
> 
> >I actually had the exact opposite problem.
> >My motor controller would barely start a move.
> >The limit switches were reported as not closed, and the 
> apparatus was in
> >a safe position to operate. The problem was due to glitches 
> on the limit
> >switch cables (we actually never observed those glitches). 
> The problem
> >was reproducible in a controlled environment (engineering bench). 
> >As of today, we think it was due to cable length and cross talking.
> >We rebuild and shortened the cables. It immediately worked.
> >
> >Food for thoughts and... time for lunch,
> >
> >--
> >Emmanuel
> >
> >On Mon, 2006-11-13 at 12:56 -0600, Mark Rivers wrote:
> >  
> >
> >>Folks,
> >>
> >>We have seen failures in the past where a motor moved 
> constantly at a
> >>slow rate right past limit switches on an OMS58.  It 
> happened only on a
> >>single axis, not on all 8 axes.
> >>    
> >>
> >
> >
> >  
> >
> 
> 
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System