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auto backlash compensation setting using home switches?
« on: June 01, 2009, 09:02:33 AM »
Hi,

I have a machine i'm retrofitting (Dyna 2400) which has limit/home switches specifically designed to have no hysteresis, for use in an automatic backlash compensation routine that the original controller had.

Can Mach automatically set backlash numbers during the homing routine using the limit/home switches?  if so, how?

Thanks,
Mike
« Last Edit: June 01, 2009, 09:09:26 AM by Mike944 »

Offline Jeff_Birt

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Re: auto backlash compensation setting using home switches?
« Reply #1 on: June 01, 2009, 09:53:15 AM »
The switches on the Dyan 2400 are nice switches but they most certainly do have hysteresis. The backlash measurement on the stock controller was a ballpark figure that gave you an idea if an axis or switch was sticky.

Backlash compensation on a mill, except for certain situations, is not very helpful. The cutting force will push the table around taking up any backlash so the compensation is not accurate. If you are only engraving or cutting circles you may see some improvement.

To answer your original question, Mach won't measure the backlash like the stock controller did. You might look into writing your own homing routine with some macros and brains.
Happy machining , Jeff Birt
 
Re: auto backlash compensation setting using home switches?
« Reply #2 on: June 01, 2009, 11:09:14 AM »
Hi,

I have a machine i'm retrofitting (Dyna 2400) which has limit/home switches specifically designed to have no hysteresis, for use in an automatic backlash compensation routine that the original controller had.

Can Mach automatically set backlash numbers during the homing routine using the limit/home switches?  if so, how?

Thanks,
Mike

You *could* write a macro to do that, except I don't believe the backlash compensation values are accessible.  AFAIK, they are stored in the XML, and read in at startup, but there is no programmatic way of changing them on the fly.  Besides, there's no reason to want to set them each time you startup the machine.  Backlash should be stable farily long-term, so you can set and forget.  And, the value you set is usually a compromise, as backlash is rarely constant across the machine travel, so you typically come up with an average value, or measure it at the location where you do most of your work.

Regards,
Ray L.

Regards,
Ray L.
Regards,
Ray L.
Re: auto backlash compensation setting using home switches?
« Reply #3 on: June 01, 2009, 01:27:52 PM »
Yeah, i guess you're right.   The backlash should not change constantly.   I guess i was just looking for a way to duplicate the original controller's behavior.

Thanks.