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Mach3 probe problem
« on: February 23, 2011, 12:14:17 AM »
I am using mach3 with machblue.set.
I set up my probe and grounded the mill head so that the tool tip could activate on my probe plate.  When I activated the probe ... it went down to touch and when it made contact ... it tried to go down instead of retract the standard distance?  I had set the thickness of my probe plate as a positive number. 

What is going on here?  Why did it go down, touch off, then go down more instead of retracting.  Sometimes it works correctly.... sometimes not.  I don't think I have any noise on the lines and even if I did ... would this happen?

Could relative vs absolute gcode setting have anything to do with it?

Any feedback/advice appreciated.

Offline Hood

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Re: Mach3 probe problem
« Reply #1 on: February 23, 2011, 03:10:15 AM »
You would really need to attach the VB you are using for the probe routine, someone may find a problem with it.
Hood

Offline Tweakie.CNC

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Re: Mach3 probe problem
« Reply #2 on: February 23, 2011, 05:34:52 AM »
Just a guess but if the Z axis DRO has not been zeroed (suppose it reads 50.0000) then the Z axis will go down to get to 5.0000 (or whatever your touch off standard distance is) rather than up.
Unless your probing routine takes care of the G90 / G91 then yes it will make a difference.
As Hood suggested post your VB and check that you have everything set correctly in the screen set.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Mach3 probe problem
« Reply #3 on: February 23, 2011, 11:11:02 PM »
Do I need to zero before using the probe?
That would explain the random behavior.  Can anyone confirm this?  I will run some tests when I have time.

Here is the code executed in machblue.set when I click the probe icon...

Code: [Select]
Rem VBScript to probe in the z axis

If GetOemLed (825) <> 0 Then 'Check to see if the probe is already grounded or faulty
Code "(Z-Plate is grounded, check connection and try again)" 'this goes in the status bar if aplicable
Else
Code "G4 P1" 'Pause 1 seconds to give time to position probe plate
PlateOffset = GetUserDRO(1151) 'Get plate offset DRO
CurrentFeed = GetOemDRO(818) 'Get the current feedrate to return to later
Code "F4" 'slow down feedrate to 4 ipm

Rem Probe in the z direction
ZNew = GetDro(2) - 2 'probe move to current z - 2 inches
Code "G31Z" &ZNew
While IsMoving() 'wait for probe move to finish
Wend

ZNew = GetVar(2002) 'read the touch point
Code "G0 Z" &ZNew 'move back to hit point incase there was overshoot
While IsMoving ()
Wend

If PlateOffset <> 0 Then
Call SetDro (2, PlateOffset) 'set the Z axis DRO to  plate thickness
Code "G4 P0.25" 'Pause for Dro to update.
ZNew = PlateOffset + .25
Code "G0 Z" &ZNew 'put the Z retract height you want here
Code "(Z axis is now zeroed)" 'puts this message in the status bar
End If

Code "F" &CurrentFeed 'Returns to prior feed rate
End If

Offline Tweakie.CNC

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Re: Mach3 probe problem
« Reply #4 on: February 24, 2011, 02:25:50 AM »
Yes, zero the Z axis DRO before using the routine. Better still include DoOemButton (1010) at the start of your code.


Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.