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Author Topic: Machine Coordinates ????  (Read 9682 times)

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Offline Chaoticone

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Re: Machine Coordinates ????
« Reply #10 on: December 17, 2007, 03:54:05 PM »
Stiriling is right. I can't test the issue as I have seperate homes. I wonder if the VB in the ref. all home button could/should be modified for your application. Do you get a limit switch error when it tries to home? What kind of hardware are you using? A BOB, Grex, etc. ?

Brett
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Offline Hood

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Re: Machine Coordinates ????
« Reply #11 on: December 17, 2007, 04:33:03 PM »
I dont see why it would make any difference where or how the switches were connected. On my Lathe I have all the limits into one pin, I do however have seperate homing switches but that is because I am using the Index homing feature on Eds board and its best to have seperate homes.
 As far as Mach is concerned it starts the homing process, it knows which axis is moving and as soon as it sees a limit switch that is configured for that axis it stops then reverses until the switch again shuts. So if all the switches are in series and set up to one Pin it will just look to Mach as if one switch has opened and then shut again.
 I may be wrong, I often am ;)

Hood
Re: Machine Coordinates ????
« Reply #12 on: December 17, 2007, 05:46:37 PM »
Do you get a limit switch error when it tries to home?

Yes I do!

Quote
What kind of hardware are you using? A BOB, Grex, etc. ?

Hobby CNC  ... 4 Axis HCNCPRO Driver Board Kit


Thanks
Bill

Offline Hood

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Re: Machine Coordinates ????
« Reply #13 on: December 17, 2007, 05:49:46 PM »
Do you get a message saying Home Switch active or something like that? Is it only after your Z Axis has hit the switch? If yes to both then that is what I would expect if your switch was doing what I think its doing.
Hood
Re: Machine Coordinates ????
« Reply #14 on: December 17, 2007, 05:52:26 PM »
Hood,

1. Yes
2. Yes

Whats should I do?

Thanks
Bill

Offline Chaoticone

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Re: Machine Coordinates ????
« Reply #15 on: December 17, 2007, 05:57:26 PM »
Sounds like noise to me or a bouncing switch. The test Hood described will help narrow this down.

Brett
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My guard dog is not what you need to worry about!

Offline Hood

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Re: Machine Coordinates ????
« Reply #16 on: December 17, 2007, 05:57:42 PM »
Throw your switches away ;)
Seriously though its either noise (which I doubt) or your switches dont open very well. What is happeneing is Mach homes, the switch opens and Mach reverses. But because the switch isnt opening correctly Mach sees it closing again and stops the reversing but then it opens again and Mach sees that limits are active so wont continue withthe homing.
 Best thing to do is wire up an on/Off toggle switch and keep your Ports and Pins set up the same way, have the toggle closed, do a home, open the toggle and Mach should reverse. Close the toggle and Mach should start the next axis etc etc.
 If this works correctly then you need to look either at just thaat one switch or all of them and see if either your trigger is not opening them enough or if they are just poor switches.

Hood

Offline Hood

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Re: Machine Coordinates ????
« Reply #17 on: December 17, 2007, 06:00:45 PM »
BTW the reason I am thinking it wont be noise is that you are not getting erroneous triggers apart from when a switch is actually hit, if it was noise I would think you would get limits going off at all different times.
Hood
Re: Machine Coordinates ????
« Reply #18 on: December 17, 2007, 06:26:30 PM »
The switches are good I have testes them and the are very tight and accurate in nature. I don't know that on a millisecond scale but the are repeatable with the DRO down to .0006 so I think they are fine they are a good quality blade with a roller on them.

I don't think its noise because as Hood pointed out they are not erratic in behavior.

Bill

Offline Hood

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Re: Machine Coordinates ????
« Reply #19 on: December 17, 2007, 06:41:06 PM »
As I said in the previous post I would test with a toggle switch (On/off) and if that works then you can go onto using one of your limits. If that works then add to the series and see where it fails. It could just be that your Z switch is dodgy. Testing with Mach to see when they open is not really the best test, granted it will show they are opening at the same repeatable point each time but if the switches are bouncing Mach will see that where you might not.
Hood