Re: Learning BDI Emc - Outputs

[Ray <rehenry-at-up.net>]

Ian

No.  I think that the index pulse is only active with the stg and ppmc stuff. 
On my stepper mill I use two switches in series one closes when the axis 
touches it,  That lights up an opto interrupter that detects a small tang on 
one of the drive pulleys.  That pulls the home pin.

Like you suggest, I would think that you could do something similar with one 
phase of a stepper driver and get somewhat better homing accuracy.  At least 
it would work if the home switch always closed within one full step.

HTH

Ray


On Monday 07 January 2002 09:43 am, you wrote:
> Hi Ray,
>
> From: "Ray" <rehenry-at-up.net>
>
> > If you change the polarity of the home switch pin, it will do exactly
> > what you are suggesting that it should.  If you use the stg or ppmc
> > definitions
>
> it
>
> > will not only look for the home switch but a z index pulse as well.
>
> Does this mean what I think it does, that you can already arrange within
> EMC for the HOME position to need both a limit switch set and a pulse on
> the axis to believe that the machine has truly homed? I had been thinking
> of having to produce a set of little logic boards to AND the limit switch
> and the signal to one coil of the motor together to get a reliable HOME
> position. Will it work for all axes and with steppermod or frequmod?
> Thanks,
>
> Ian