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Author Topic: Hard Limits and Soft Limits  (Read 2519 times)

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Hard Limits and Soft Limits
« on: December 10, 2009, 05:49:28 PM »
Now that my quill drive is up and running, and after putting it off for FAR too long, I'm finally going to start putting limit switches on my knee mill.  But I'm not entirely clear on exactly how to set them up.  On the quill in particular, I want to preserve as much usable travel as possible (since there's only 5-1/8" to begin with) between limits.  So, my question is, how are limits normally setup?  I can see a couple of different ways to do it:

1) Setup hardware limits so they trigger somewhere inside the "hard" limits, allowing perhaps 1/4" or so for a "safe" zone?

2) Setup hardware limits to they trigger *just* short of the "hard" limits, then use soft limits to create a "safe" zone.

I'm assuming the safe zone should, ideally, be just long enough to allow the axis to coast to a stop from a full rapid before hitting the hard stop.

Are there other options?  How are limits normally setup and used?

Regards,
Ray L.
Regards,
Ray L.

Offline Hood

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Re: Hard Limits and Soft Limits
« Reply #1 on: December 10, 2009, 05:58:37 PM »
Limit switches are normally very close to the extremities of travel but obviously you should test to see how far the axis will take to coast to a stop from full rapid and it will obviously be further on the Z minus than Z positive.
Soft limits are set up to the exact position of your limits and the Slow Zone is what you use to make sure you dont actually overshoot when doing a full rapid.
Hood
Re: Hard Limits and Soft Limits
« Reply #2 on: December 10, 2009, 10:47:44 PM »
Hood,

Thanks!  I'll give it a try!

Regards,
Ray L.
Regards,
Ray L.