Tool zeroing by aligning the machine manually and setting the DRO to zero is a time consuming process. Using a touch plate to set the zero greatly improves accuracy. For my machine, there was a touch plate available, but it plugged into the side of the car and needed to be set out manually and removed for the machine to work.
I wanted to make it so it wasn’t necessary to leave the terminal to get the machine to zero. The best way I could think of doing this was to set a fixed touchplate to the side of the bed (just outside of the work area) and slightly below the bed of the table.
This way, I am able to reliably reset the 0 for the Z axis of the machine even if a full sheet is on the table.
The touchplate is set to some distance below the bed and this is included in the macro so the offset can be compensated for.
Below is a short video demonstrating the tool zeroing cycle.
'M200 Auto Zero-ing Mach3 Script 'Created: C. Stewart email@example.com 09/01/2017 Private Sub home() Dim ZprobeDepth, ZfeedRate, Zsafe, XcoordTouchPlate, YcoordTouchPlate, Ret, CurrentZMachinePos, ZprobCoord Dim isZeroPlateTouched As Boolean isZeroPlateTouched = false ZprobeDepth = -30 Zsafe = 30 ZfeedRatePlunge = 100 ZfeedRateRetract = 1000 FeedRateJog = 2000 ZdepthTouchPlate = -3 XcoordTouchPlate = 45 YcoordTouchPlate = 95 Ret = MachMsg("Is the tool at safe Z? i.e. clear of all obstructions? If no, click 'NO' And jog To safe Z Then re-run ", "Check Z!", 4) If Ret = 6 Then Message( "Safe Z Confirmed" ) ElseIf Ret = 7 Then 'Abort 'Trigger E-stop DoOemButton(1021) Message( "jog To safe Z Then re-run " ) Exit Sub End If 'Move to the touch plate Code "G53 X" & XcoordTouchPlate & " Y" & YcoordTouchPlate & "F"& FeedRateJog Message( "Auto Tool Zeroing..." ) 'Check if the touch plate has been hit If IsSuchSignal (22) Then 'Call SetUserDRO( 2, 0.00 ) 'Get the current machine Z co-ordinate CurrentZMachinePos = GetABSPosition(2) ZprobCoord = CurrentZMachinePos + ZprobeDepth code "G31 Z" & ZprobCoord & " F" & ZfeedRatePlunge While IsMoving() If GetOemLed(825) = -1 Then isZeroPlateTouched = true Else isZeroPlateTouched = false End If Wend Call setMachZero(2) 'zero the Z axis 'Call SetUserDRO( 2, ZdepthTouchPlate ) code "G53 Z" & Zsafe & "F" & ZfeedRatePlunge End If If (isZeroPlateTouched) Then Message( "Tool Zero-ed: " & isZeroPlateTouched) 'Move back to machine zero X and Y Code "G53 X0 Y0" & "F"& FeedRateJog Else Message( "Tool Zeroing failed: " & isZeroPlateTouched ) MachMsg( "The tool failed to zero automatically. Please check and retry", "Tool Zero Failed!", 0) 'Trigger E-stop DoOemButton(1021) Exit Sub End If End Sub