On 2/8/2017 8:15 PM, Jon Elson wrote:
> On 02/08/2017 11:34 AM, [email protected] wrote:
>> I don't have a physical stop on my Z axis, putting one in would be a PITA.  
>> The drive is exceptionally strong and it would be problematic to stop the 
>> axis that way.  If you're an idiot and jog it that way prior to homing, you 
>> can dismount the axis.
>>
>> There is a homing switch at Z+.  It sounds desirable to halt + movement when 
>> that switch is tripped, AND not homed, AND not in the actual homing 
>> sequence.  But NOT stop - movement, otherwise you'd jog it upwards, get it 
>> stuck, and no way to jog down.
>>
>> How difficult would it be to do that?
>>
>>
> LinuxCNC includes provisions for this.  Set
> HOME_IGNORE_LIMITS = YES in the .ini file for that axis.
> The trick, of course, is to make sure the home position is
> moved off that switch.  So, you have to set a
> HOME_OFFSET = -0.1
>
> or something like that, so it jogs off the home switch
> sufficiently to UN-trip the switch.
> Then, set your MAX_LIMIT to less than that distance (or zero).
>
> This way, it will home up to the switch, move down by the
> HOME_OFFSET amount and then set soft limits so you cannot
> reach the switch.
>
> Jon
>
Hmm, could I also AND the input pin with NOT IS_HOMED for Z before tying 
it in as  a z+ limit?  So the limit switch can only apply prior to homing?

Thing is, I like to preserve the capacity to travel all the way up.

Danny


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