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Author Topic: Homing sequence and Z-Axis Home Offset?  (Read 13363 times)

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Homing sequence and Z-Axis Home Offset?
« on: October 31, 2006, 11:33:00 AM »
Hi Guys -- I am just finishing up converting a New Hermes engraver to CNC with the MACH3 controller. I have all my limits and home switches adjusted and working properly but I am having a problem with homing the Z axis (engraver tool bit). I would like to be able to make the Z axis move to a specific position away from the Z Home switch, rather than to have it stop immediately upon actuation of the Home switch. Is that possible in MACH3? Also, could the SEQUENCE of Axes be changed? In other words can I make the system Home first the Z, then the X, then the Y?

Thanks!

Mike
Some people are like a Slinky -- not much good for anything, but it brings a smile to your face when you shove it down a flight of stairs.

Offline Chaoticone

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Re: Homing sequence and Z-Axis Home Offset?
« Reply #1 on: October 31, 2006, 11:54:21 AM »
Hi Mike,
    I think you can change the z home by going to Home Off and entering a value. The homeing sequence can also be changed. Let me play with it a minute. In the new version, there is also a safe z set up in config. This may do what you want.
;D If you could see the things I have in my head, you would be laughing too. ;D

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Re: Homing sequence and Z-Axis Home Offset?
« Reply #2 on: October 31, 2006, 12:04:10 PM »
I think to change the sequence you will have to do this in screen 4. You can change it with VB script ( I know nothing of this ) or have the button perform Gcode moves.
;D If you could see the things I have in my head, you would be laughing too. ;D

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

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Re: Homing sequence and Z-Axis Home Offset?
« Reply #3 on: October 31, 2006, 12:11:49 PM »

In the new version, there is also a safe z set up in config.

I tried this, I set the safe z set up as global, allow z moves, work cord., value .250.
It moved the z to .250, moved the x & y to 0, then the z to 0.
This is a nice feature.
« Last Edit: October 31, 2006, 12:14:12 PM by Chaoticone »
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Homing sequence and Z-Axis Home Offset?
« Reply #4 on: October 31, 2006, 02:20:28 PM »
Thanks for your reply!.

In my version of MACH3 (R1.84.001) there is a check box in "Config, Logic" tab, labeled "Use Safe_Z" but I do not see any way to enter specific parameters that define Safe_Z.  I also can not find the screen that you show in your post. It must be in a different version of MACH3.  Also, it seems that the "Home Off" settings in the Home/Limits tab only affect the DRO value during Homing, but does not change the actual position of the axes. For example, if I put the value 5.00 for the X Home Offset, the axis will stop on the Home switch as usual, but the DRO will indicate a position of +5.00.

I think the Safe_Z function will do what I need but I may have to switch to a different version of the program. Any further assistence would be greatly appreciated.

Thanks again!
Some people are like a Slinky -- not much good for anything, but it brings a smile to your face when you shove it down a flight of stairs.

Hood

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Re: Homing sequence and Z-Axis Home Offset?
« Reply #5 on: October 31, 2006, 02:53:30 PM »
I dont think you can have the Z move off home for a set distance, the way the home works is the axis moves until the switch is hit then it backs off slowly until it comes off the switch, that is your home position. You could use seperate home switch and place it where you want your home to be if it is what you are wanting.
 For the homing sequence it should move Z First then Y then X, is this not happening with you or am I misunderstnding.
Hood

EDIT
 just noticed the homing and limits page that Brett posted, I have never noticed the "HomeOff" column before so possibly that is what it is for. Unfortunatel I cant test it as I am not at the mill, just have Mach on the home computer and its not easy to actually see what that function does without having physical limits set.
« Last Edit: October 31, 2006, 02:59:46 PM by Hood »

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Re: Homing sequence and Z-Axis Home Offset?
« Reply #6 on: October 31, 2006, 03:13:37 PM »
Yes Hood, that is exactly what happens, at least on mine. I think X-ray's too. The x&y first then the z.
;D If you could see the things I have in my head, you would be laughing too. ;D

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

Hood

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Re: Homing sequence and Z-Axis Home Offset?
« Reply #7 on: October 31, 2006, 03:20:52 PM »
Brett are you saying your X and Y move together then the Z when homing?

Hood

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Re: Homing sequence and Z-Axis Home Offset?
« Reply #8 on: October 31, 2006, 03:33:20 PM »
Yes.
;D If you could see the things I have in my head, you would be laughing too. ;D

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

Hood

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Re: Homing sequence and Z-Axis Home Offset?
« Reply #9 on: October 31, 2006, 03:43:54 PM »
Can you go to the operator menu then down to Edit button script, your home button should now flash, click on it and what does the VB say?
Hood