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Author Topic: Z Axis not zeroing to switch  (Read 4026 times)

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Offline bowber

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Z Axis not zeroing to switch
« on: July 18, 2007, 12:23:33 PM »
Hi all

Quick intro, I'm new here and have a Denford Easimill converted to Mach 3 and micro stepping drivers.

Everything has been ok so far but last night I set up my home switches using the N/C contacts on 3 micro switches, all wired up and set the machine to home, it went the wrong way so I changed it back to home positive, my home is top right corner of the mill table.

Z axis moved up homed and off by the 3 mm as set, the same with the X & Y.

Now though if say I restart with the Z down any amount then try homing the Z moves up by a few mm and stops then the X & Y home properly, I can keep doing this until the Z actualy does hit the switch and then it all work correctly. Wierd.

Anyway I've tried setting it back up and also tried setting the home switches as + limits, and that doesn't work either, I just get a constant limit switch activated.

Is this something I'm doing wrong or is it a bug.

Mach 3 version 2.0.065.

Thanks
Steve

Hood

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Re: Z Axis not zeroing to switch
« Reply #1 on: July 18, 2007, 03:26:55 PM »
Try setting the debounce higher, try 2000 and if it helps you can try lower. You will find it on the  Config menu, General Config page. Not quite sure I understand your bit about the +limits but could it be you need to change the active low setting for them?
Hood

Offline bowber

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Re: Z Axis not zeroing to switch
« Reply #2 on: July 18, 2007, 03:53:45 PM »
Thanks Hood

Just came in to say I'd found it was signal noise.

I had a bit more time tonight so I went through it consistantly instead of last night when I'd just got them fitted and wanted to get them working immediatly :-)

The Z axis limit switch wires run with the Z stepper wiring for most of the distance back to the control box, I've run seperate wiring now. This was also the problem with the limit switch being detected when I have the home switches as limits as well.

I'm still getting intermitent noise on the X or Y when it's used as a limit but I'll try the debounce level or just run the wires through a different route.

My home switches are also the axis limits in the + direction hense the mention of + limits.

Thanks again
Steve

Hood

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Re: Z Axis not zeroing to switch
« Reply #3 on: July 18, 2007, 04:00:20 PM »
do you have the cables grounded at one end only?
Hood

Offline bowber

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Re: Z Axis not zeroing to switch
« Reply #4 on: July 19, 2007, 04:42:07 AM »
Hi Hood

I'm couldn't find any shielded wiring so it's not grounded at either end.

Steve

Hood

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Re: Z Axis not zeroing to switch
« Reply #5 on: July 19, 2007, 12:43:53 PM »
You should really have shielded wires for limits, 5V is not the best for this application and the difference between High and Low is fairly small so is prone to noise triggering them. If you do get shielded cables  later on make sure you only ground at one end.
Hood

Offline ardor

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Re: Z Axis not zeroing to switch
« Reply #6 on: July 19, 2007, 07:22:51 PM »
Cables for mouses, keyboards, etc are shielded.

Get a 12 ft. extension, whack the ends off.

Lotsa pretty wires.

Ashby
There is no approved dental use for WD40

Offline bowber

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Re: Z Axis not zeroing to switch
« Reply #7 on: July 19, 2007, 07:37:47 PM »
Cables for mouses, keyboards, etc are shielded.

Get a 12 ft. extension, whack the ends off.

Lotsa pretty wires.

Ashby

I din't know that!

By the way shouldn't it be micees :-)

Ok I'm a little drunk.

Steve

Hood

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Re: Z Axis not zeroing to switch
« Reply #8 on: July 20, 2007, 07:05:31 PM »



By the way shouldn't it be micees :-)


Steve

Nope its meesis ;)

Most cables from mice dont have shielding, atleast from my experience but Parallel cables, serial cables and monitor cables usually do.

Hood