Re: [CAD_CAM_EDM_DRO] Re: Rotary Axis home and/or limit switches

The issue everyone is missing, I think, is that the OP's table goes round
and round and round, and everytime it does, the home/limit is triggered. The
ability to home is not a problem.

But he has configured Home as Limit, and that is the problem. He has not
replied though, so we cannot know.

If a limit switch is required, but has a complex relation to other axis, I
think the easiest would be a Pic controller or PLC. Otherwise another any
old junk PC running Qbasic and interfacing to the parallel port.

Roland

On 8 February 2010 01:37, Torsten <torsten@...> wrote:

>
>
>
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com <CAD_CAM_EDM_DRO%40yahoogroups.com>,
> "ya_nvr_no" <yanvrno@...> wrote:
> >
> > I have added a couple of rotary axis's But am having an issue with coming
> up with a good way to home them. One switch gives me a home position but if
> I rotate one revolution the switch is made again. I am using CNCpro, it uses
> a limit switch as the home switch.(would another program handle this
> better?)
> >
> > So for example, an issue on the B & C axis.
> > Do I home at somewhere >90 degrees then move the B axis to the vertical
> position once I know what that angle is? Manual Zero this location.
> > Home the C axis and then rotate it ~180 to find the center of the
> truncated 360 degree rotation? Manual Zero this location
> > And on an A table axis I would be limited to less than 360 degrees.
> >
> > My options are:
> > Using a M code or manual toggle switch to disable the homing/limit
> switches after homing
> > or
> > Using both home and limit switches, create a logic IC circuit/or PLC that
> determines conditions.
> >
> > I've searched but find no info on how this is handled.
> > There has to be a straight forward way to handle this.
> > Thanks for any HELP/Direction
> >
>
> This is usually entirely up to the controllers Software how homing is done
> on the Rotary Axes.
> The Software I am using will look for the trigger of the Switch for Homing
> only when specificly executing a homing move.
> Then the following happens.
>
> 1) Check is trigger is allready pressed. Go step 3 if true.
> 2) Rotate fast as configured right or left untill trigger actuates.
> 3) Backoff trigger in reverse slowly untill trigger breaks.
> 4) Backoff aditional distance as configured fast and set
> machine zero for the Axes there.
>
> Durring other Machining moves this trigger is ignored.
>
>
>


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