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homing not working correctly
« on: June 29, 2012, 01:11:06 PM »
Hey guys,
When I reference my machine it no longer travels to the limit switches.  It moves a undetermined amount, no consistent amount and on all x, y and z axis. This doesn't happen all the time but mostly on my y axis. When it homes correctly it trips the switch then backs off the switch, when it does it incorrectly it does not back off it just calls that position 0.

Any help is appreciated.

Method.
"Ideas have consequence" Ravi Zaccharias

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Re: homing not working correctly
« Reply #1 on: June 29, 2012, 01:40:50 PM »
You eieher have vibration activating your switches or you have electrical noise cause Mach to see a false trigger. Try setting a Debounce Interval of 2000 in General Config page and if that helps drop it back as low as you can. Low voltage signal wiring should be properly shielded and grounded so if you have not done that it may be worth considering.
Hood
Re: homing not working correctly
« Reply #2 on: June 29, 2012, 01:44:49 PM »
Ok, ill give it a try when I get home.


Thank for the help, I'll post my results later.
"Ideas have consequence" Ravi Zaccharias
Re: homing not working correctly
« Reply #3 on: June 29, 2012, 05:28:57 PM »
My Y axis was the one that gave me the most trouble, so first of all I swapped the Z and Y switches and tested to see if it was a faulty switch. It gave me the same issue.

Then I unplugged the power to my work light and router to see if it was a issue with shielding and that made no difference either.

 Then I did what you recommend and set the debounce value to 2000 and it worked, it was able to home properly.  I brought the value down to 100 and it still homed correctly but..... I the motor made a moaning noise when it moved in the opposite direction after the switch was triggered. I took off the motor to see if the axis was under load and it moved very easily with two fingers.

Any ideas about the motor? I was thinking of switching the Z and y axis motors to see it it still happens.

What does the debounce 2000 value pertain to? Will it affect the programs I run?

I have more questions but I'll wait till I hear your reply.

Thanks for the help!:-)
"Ideas have consequence" Ravi Zaccharias
Re: homing not working correctly
« Reply #4 on: June 29, 2012, 05:58:48 PM »
Btw, it's a stepper motor.
"Ideas have consequence" Ravi Zaccharias

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Re: homing not working correctly
« Reply #5 on: June 29, 2012, 06:42:54 PM »
The Debounce is just a filter for the input signals to Mach, basically Mach will not act on a signal unless it persists for more than the set time. Noise is very sporadic and is not consistent so setting the debounce usually helps. Personally I like to have the debounce at 0 but with you getting 100 working I wouldnt worry too much as that showed you were only getting slight noise.

Your stepper problem is not likely to be related to the debounce, its been a long time since I used steppers so others may have more of an idea but maybe increasing the pulse widths in Motor tuning may help.
Hood