Re: Rotary Axis home and/or limit switches

--- In CAD_CAM_EDM_DRO@yahoogroups.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.