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Author Topic: Z Homing Bug?  (Read 2640 times)

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Z Homing Bug?
« on: January 05, 2009, 05:07:39 PM »
On my setup I've got 3 homing switches, X, Y, Z.  After each part I run G28.1 to home each axis just in case any steps were lost.  Z, Y, and X axis slowly home, hit the switch, then back off a bit. The Z axis, though, is not always consistent on it's homing procedure.  Most times it raises until the homing switch is tripped, then backs off a bit. This is then referenced as zero.  It appears to get in some mode where it forgets to back off the switch.  I'll "reference home" and it will move until the switch is tripped and not back off the switch. This then becomes the new Z zero and the tool becomes .050 higher than originally.   X and Y axis will continue in the home routine with each one backing off their respective switches.  It is very bizarre.  I've found I can go into "homing/limits" and re-set the Home Off. number and the Z axis "backing off" will start to work again. 
I haven't been able to see a pattern on when/why this happens.  Any ideas on a fix would be helpful.  Thanks


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Re: Z Homing Bug?
« Reply #1 on: January 05, 2009, 05:12:46 PM »
Does the LED turn green for the Z after the home? If it does then Mach has seen the switch closing again so  its most likely a bouncing switch or could be noise. Increase the Debounce Interval and see if it helps, first try 2000 and if it does step down until you get the problem again then step back up. The real problem would be better fixed though so if it does prove to be that debounce works you should really try another switch or check your shielding is correct.
Re: Z Homing Bug?
« Reply #2 on: January 06, 2009, 10:47:02 AM »
Didn't think about that.  Thanks for the help.  It is working now so I'll give it a try when it acts up again.  Roger