Wafersaw: Change of shutdown procedure

Eric Perozziello eap at gloworm.Stanford.EDU
Mon Jun 6 11:39:07 PDT 2005



Hi Elmer

This is a problem-  it should not hunt for limit switches
after the "normal" shutdown procedure!  Only after a
reset.   In fact, after the normal reset with the
Emergency stop, and then re-starting, everything
should stay exactly as it was before, including the
y-offset for the blade.

-Eric





On Mon, 6 Jun 2005, Elmer Enriquez wrote:

> Eric Perozziello wrote:
>
> >It should be ok to push the Emergency Stop button,
> >so if it's doing something funny, we need to find out why.
> >
> >When you disable, it has the same effect as pushing
> >the emergency stop button, so I don't think changing the
> >procedure is going to help.
> >
> >I've not seen it do anything strange since the servo repair,
> >so if it is, we should find out what's causing it (procedures
> >or hardware problem).
> >
> >-Eric
> >
> >
> >
> >On Fri, 3 Jun 2005, Jia Feng wrote:
> >
> >
> >
> >>Hi, wafersaw users:
> >>
> >>I just noticed this important change of procedure on coral. I am copying it
> >>FYI. The problem has been occurring repeatedly recently.
> >>
> >>Change of procedure:
> >>
> >>-- Do not press the "Emergency Stop" button when you're done with the tool.
> >>This takes the x,y and z axis motors to their limit switches.
> >>
> >>-- When shutting down the tool;
> >>
> >>      - Push the "Stop" button
> >>
> >>      - Turn off the air supply
> >>
> >>      - Turn off the pump
> >>
> >>      - DO NOT press the "Emergency Stop" button
> >>
> >>
> >>Jia
> >>
> >>
> >>
> >>
> Eric,
>      The wafersaw has gone done 3- 4 times since the servo motor was
> replaced.   The z and y axis motors would drive pass their limit
> switches.  I had to replace the -28 volt fuse once and the +28 volt
> once.  As far as pressing the "emergency stop" button and the disabling
> the tool being the same thing; their not.  If you press the "emergency
> stop" button, the system would try to rehome (find the limits) upon
> start-up.  If you DO NOT press the "emergency stop" and just disable the
> tool,  the motors will start-up from their current position and will not
> try to find the limit switches.  TRY IT.
>      As far as finding out why it's behaving funny, we believe its
> caused by defective limit switches.  We will replace them when the new
> ones arrive.  I've heard that Len has replaced the switches several
> times in the past.  Perhaps pressing the "emergency stop" every time the
> saw is used puts undue stress on them.
>
> - Elmer
>
>




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