Basic z-height probe macro trouble

Hi all,

I am trying to make a useful z-height thing to run during an M6 tool change call. This is for a router-style machine where the tool height is variable because of the collet-holder, so i want to read and zero the tool at each change.
But Mach does not seem to work right if i try to call G31 two times in the same macro. Does this make sense?

Additionally, it seems that my chinese break-out-board w/ Ethernet SmoothStepper does not implement GetVar(2002), so i'm loading the z-height from the DRO.

That seems to work fine for the first run of G31, but the second time G31 runs, it will not stop its negative z travel before it reaches the point where the first G31 stopped! Yikes! During that time, i can see the "probe" LED turn on and off in the "diagnostics Alt-7" page, so signals are going places.

Once we pass the point where the first G31 stopped, it will respond to probe input and quit its negative z travel. Whew.

But the DRO value for z, whether we check
GetDRO(2)
or
GetOEMDRO(1002)

always contain the z-height from the first run of G31, never the second.

Banannas! Anybody know a fix? I've spent all day thinking i was either crazy or braindead trying to fix this before finally deciding it must be a bug of some sort, or??

Code:

---

slowFeed = 10 'in/min

OldProbeTouch = 0
NewProbeTouch = 0
ToolHeightDifference = 0


currentZ = 0
newZ = 0




allowedBreakThrough = 0.002 '2 thousandths of an inch


ToolChangeX = GetUserDRO(1200)         
ToolChangeY = GetUserDRO(1201)
ToolChangeZ = GetUserDRO(1202)      'use Settings / tool change location / for touchplate location


GageH = GetOEMDRO( 1001 )            'Gage Block Height from offsets screen *upper left hand one




     
Code "G53 G0 Z" & ToolChangeZ ' go to tool change z location FIRST
Code "G53 G0 X" & ToolChangeX & "Y" &ToolChangeY ' go to tool change x & y location SECOND


'FIRST PROBE CHECK'
       
        Code "G31 Z" & -3  & " F" & slowFeed          'G31 is probe command
                                                            'enabling G53 (absolute coordinates' for z argument could help us target the bed of the machine
                                                            'or let soft limits help prevent a crash?
                                                            'If we don't find the probe within the z move
                                                            'we throw an error
                                                           
        While IsMoving()
                Sleep(10)
        Wend
             
'        If GetOEMLed(825) = True Then        'Probing successful
                'OldProbeTouch = GetVar(2002)      'Exact height touch plate was contacted  // DOES NOT WORK ON CHINESE MACHINES?
                OldProbeTouch = GetDRO(2)
                'OldProbeTouch = GetOEMDRO(1002)
                code "g4 p.5"
                Code "G1 Z" & OldProbeTouch      'Go there (corrects for potential over-run) 
                While IsMoving()
                Wend
             
             
'        Else
'                Message("Zero not achieved - Check probe and try again manually")
'        End If
'FIRST PROBE CHECK'


        MsgBox ("hit cycle start to begin second probe")
        SystemWaitFor (Start) 'Pause macro to jog the Z axis close to the switch




'SECOND PROBE CHECK'
          Code "G53 G0 Z" & ToolChangeZ ' go to tool change z location
        Code "G31 Z" & -3  & " F" & slowFeed          'G31 is probe command
                                                            'enabling G53 (absolute coordinates' for z argument could help us target the bed of the machine
                                                            'or let soft limits help prevent a crash?
                                                            'If we don't find the probe within the z move
                                                            'we throw an error
       
'        If GetOEMLed(825) = True Then        'Probing successful
                'NewProbeTouch = GetVar(2002)      'Exact height touch plate was contacted // DOES NOT WORK ON CHINESE MACHINES?
                NewProbeTouch = GetDRO(2)
                'NewProbeTouch = GetOEMDRO(1002)
                code "g4 p.5"
                Code "G1 Z" & NewProbeTouch      'Go there (corrects for potential over-run) 
                While IsMoving()
                Wend
             
             
'        Else
'                Message("Zero not achieved - Check probe and try again manually")
'End If
'SECOND PROBE CHECK'








ToolHeightDifference = OldProbeTouch - NewProbeTouch






currentZ = GetDRO(2)
newZ = currentZ - ToolHeightDifference






Call SetDRO(2, currentZ) 'set work coordinate z0 based on difference between old and new tool






newZMin = NewProbeTouch - GageH - allowedBreakThrough




Message("Old Height " & OldProbeTouch & " New Height " & NewProbeTouch & " Toolheighdifference " & ToolHeightDifference & " new Z should be: " & newZ & " new Zmin should be: " & newZMin)




'  SetOEMDRO(158, newZMin)    'OEMDRO 158 is the z min limit
                                'set it to be at the tip of the tool when the touchplate is removed

---