Re: Homing problem in Mar 15 build

["Darrell Gehlsen" <darrell-at-machinemaster.com>]

If the system would hit the limit switch, then back out slow until the
switch tripped the other way with the option of looking for an index, that
would allow you to use the same switch for homing and limit.
Darrell

----- Original Message -----
From: Tim Goldstein <tgoldste-at-mlh-services.com>
To: Multiple recipients of list <emc-at-nist.gov>
Sent: Monday, March 27, 2000 10:30 PM
Subject: RE: Homing problem in Mar 15 build


>
> Jon,
>
> You are correct about the process. it has been that way for the last 3 or
4
> builds. Previous to that it was just hit the switch and stop. But, as I
> mention on this one it is acting quite abnormal and seems to have lost the
> repeatability I had in homing since last summer (while the old method was
> theoretically not as accurate it was pretty darn close).
>
> While I agree that using the index on an encoder is more accurate, the
micro
> switch I am using seems to give me +-.0005 which is good enough for me.
>
> Tim
> [Denver, CO]
>
> > -----Original Message-----
> > From: emc-at-nist.gov [emc-at-nist.gov]On Behalf Of Jon Elson
> > Sent: Monday, March 27, 2000 10:20 PM
> > To: Multiple recipients of list
> > Subject: Re: Homing problem in Mar 15 build
> >
> >
> >
> >
> >
> > Tim Goldstein wrote:
> >
> > > I just tried actually homing with the Mar 15 build on RedHat
> > 5.2 and I am
> > > having a problem. once I contact the home switch the axis is
> > continuing to
> > > travel about .1 " then it reverses direction and backs up a few
> > thousands
> > > then it starts back in the original direction of the homing at
> > a rate of a
> > > few steps per second and keeps going for 5 or so seconds.
> > >
> > > This is unlike homing has been working. Previously the direction would
> > > reverse as soon as the homing switch was contacted and then it
> > would come at
> > > the switch again very slowly and stop the instant the contact closed.
No
> > > extra movement past the switch closing at all.
> > >
> > > Anyone else try to home under freqmod with this build? I have
> > not tried it
> > > with steppermod.
> >
> > The old homing procedure was to locate the switch, period.
> >
> > I believe the new procedure (should only be used with encoders with a
> > Z (index) channel), is to use the switch to get close to one specific
> > pulse from the Z channel, and then locate the first Z pulse after the
> > switch closes.  If you do this right, it is possible to set up a home
> > position that will precisely locate from either direction, and be
accurate
> > down to 1 or 2 encoder counts.
> >
> > Jon
> >
>
>