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Home problems
« on: July 01, 2013, 08:30:16 AM »
My machine has started doing something I don't understand when I click ref home it only moves a very short distance then re-zeros out just like it hit the home switch but it is a long way from the switch. When I go to the page where you can see the lights for the switches they are working like they are supposed to be,,,,, lights off until you make the switch then on when you make the switch. What do I need to do to get my machine to go all the way until it hits the switches at home ?

Offline Tweakie.CNC

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Re: Home problems
« Reply #1 on: July 01, 2013, 08:36:14 AM »
Strange it should just start to happen.

Have you added any new hardware / software relating to the machine ?
Have you made any changes to the wiring (route etc.) ?
Have you made any other changes to the machine ?

Tweakie.
KEEP SAFE !
Re: Home problems
« Reply #2 on: July 01, 2013, 08:45:24 AM »
I moved and had to take part of the machine apart  to move it but it is back together just like before, I have replaced stepper motors in the past and had to change settings to get it to feed ing the right direction. The machine will run parts just fine but will not go to the home switches. Where ever zero is at it will run to there. but if you click ref. home it only moves a short distance and stops like it hit a switch when it did not.

Offline Hood

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Re: Home problems
« Reply #3 on: July 01, 2013, 03:45:10 PM »
Sounds like one of two things, either machine vibration causing switches to flutter or a wire to them is loose and the vibration is breaking contact.
More likely however is noise causing the input to be seen, possibly something different in the way you routed wires or possibly something new nearby causing the noise.
You could try setting a Debounce Interval of 2000 in General Config and if it helps then reduce as much as you can.
Hood

Offline ger21

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Re: Home problems
« Reply #4 on: July 01, 2013, 04:48:59 PM »
Could be a corrupt .xml file as well. Twice I've had strange homing issues and my backup .xml fixed them right up.
Gerry

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Re: Home problems
« Reply #5 on: July 02, 2013, 03:19:11 PM »
Had same problem with my E-Stop, while I build the individual parts everything was OK. But when the cables were put together (motorcables, E-stop, switches etc.)
The noise inducted into the E-Stop cable caused it to trip.

Had to build a insulation circuit with optoisolater supplied from a seperate 24VDC PSU, now it works as intended.
Best Regards, Bo Andersen.
Re: Home problems
« Reply #6 on: July 02, 2013, 06:56:53 PM »
Ok so I guess it was some kind of noise problem because I had the home switches wired to normaly closed and now I wired them to normaly open and the machine will run all the way until it makes the switch and then stop in all 3 axis,,,,,,,,, Yea !!!!!!!! The only thing I don't understand is before when it was wired to normaly closed when it made the switch it would back off just until the switch was no made now when it makes the switch it stops there and that is it. That is OK just differant. The only other thing is the auto zero no longer works when the home switch is hit and I still have it checked in the config page,,,,, what is up with that ?
Re: Home problems
« Reply #7 on: July 02, 2013, 07:27:32 PM »
Well auto zero is working because when it homes it sets everything to zero and if I jog it off the home switch and then by hand move a stepper so that I have now lost stepps and hit ref home when it hits the switch it will rezero the only thing it will not do is if you move off home and hit the zero button then hit ref home when it gets home it will keep the number from where I hit the zero button like keeping a fixture location, I guess I just was thinking about it the wrong way. I still don't understand why it dose not back off the switch unless it is a noise problem and it thinks the switch was unmade which is where my problem started,,,,,,, yea that must be what is going on,,,,,,, why has it run all these years just fine and now it has this noise problem ? Anyway Thanks for the help guys now I can get back to making parts !!!!!!!
Re: Home problems
« Reply #8 on: July 03, 2013, 01:42:36 AM »
Ok so I guess it was some kind of noise problem because I had the home switches wired to normaly closed and now I wired them to normaly open and the machine will run all the way until it makes the switch and then stop in all 3 axis,,,,,,,,, Yea !!!!!!!! The only thing I don't understand is before when it was wired to normaly closed when it made the switch it would back off just until the switch was no made now when it makes the switch it stops there and that is it. That is OK just differant. The only other thing is the auto zero no longer works when the home switch is hit and I still have it checked in the config page,,,,, what is up with that ?
It sounds like a problem I too experienced. And like you, I changed the limit switch logic to normally open. However, the problem actually turned out to be a sticking switch (one time), and another time it was actually a broken wire. Still another time, it was a broken switch. You can actually save yourself a lot of head aches, by powering down everything, and just checking the limit switch circuits with an ohm meter. Cycle the switches on and off, to make certain the contacts are not sticking, check the wiring for continuity, etc. before taking the step of changing circuit logic, or Mach3 logic and pulling hair!

Offline Hood

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Re: Home problems
« Reply #9 on: July 03, 2013, 03:14:13 AM »
Having normally open switches is not a good idea if you are also using the switches as limits.
In fact with Mach even if you have seperate Home and Limits it is still not a good idea as Mach ignores limits whilst homing.
Hood