' This version is for Lathe use - Roger Caffin  13/08/2016
' It is a total rewrite of the original Mach3 version
' In essence, the g83 instruction in Mach3 calls this macro
' It must be in the folder Mach3/macros/machturn
'
' G83 X (ignored)  Z (required) Q (required) R (required)
' It is ASSUMED that X=0 for a lathe: there is NO X movement here
' Entry will be with Z = Zstart above the material surface
' Z is the target depth for the instruction
' Q is the maximum peck distance per cycle; actual peck may be less
' R is the 'Retract' distance: where the drill retracts to each on cycle
' Note that FeedHold does not seem to interrupt this instruction: use Stop
'
' Normally R will be above the surface of the material so that a cyclic
'  retraction to R will clear the drill bit right out of the hole.
' However, the tip of the drill can score the bore on subsequent
'  re-entries, which may be undesirable.

' There are two versions of this instruction:
' g83 (C=0) does a full slow retract to R on each cycle
' g83.1 (C=1) does a fast retract just to the start of the last cycle

' The g83(.1) instruction may be preceeded by a g98 or g99 instruction.
' g98 (ExitMode=0) causes the cycle to exit with Z = R
' g99 (ExitMode=1) causes the cycle to exit with Z = Zstart
' Note that g98 may leave the drill in an unfortunate position.

Test = false		' Debug flag
ZStart = tZStart()	' Starting Z height - OK
ZEnd = tEndZ()		' this is the Z in the G83 call - OK
Q = Abs(tInFeed())	' Q value, REQUIRED, OK
R = tZClear()		' R value, REQUIRED, OK
C = tTaper()		' g83/g83.1 flag - OK
ExitMode= RetractMode()	' g98/g99 flag - OK

XPos = tEndX()		' this is the X in the G83 call - WRONG

If Zend>= R Then	' Sanity check on target Z
'  MsgBox("Target Z > Retract value!", 16, "Sanity Check")
  MsgBox("Target Z > Retract value!")
  stop
End If

If Test = True Then	' Debug log file
  If c=0 Then
    G83="G83 (slow)"
  Else
    G83="G83.1 (fast)"
  End If
  If ExitMode=0 Then
    EMode="G98 (to R)"
  Else
    EMode="G99 (to ZStart)"
  End If
    
  LogFile="LogFile.tap"	' Found in mach3/gcode
  MyErr=openteachfile(LogFile)
  If MyErr=0 Then
    MsgBox("Couldn't open Log File")
  Else
'    MsgBox("Opened Log File")
    Code "(ZStart = " & ZStart & ")"
    Code "(Zend = " & Zend &")"
    Code "(PeckQ = " & Q &")"
    Code "(Retract = " & R &")"
    Code "(Slow/Fast = " & g83 & ")"
    code "(ExitMode = " & EMode & ")"
    Code "(EndX = " & XPos &")"
  End If
End If

' Z clearance parameter
If GetLED (2) Then
  ZClear=0.2	' mm if metric
else
  ZClear=0.01	' " if imperial
End If

' Extra feature for R below surface to keep drill tip engaged
If R < ZStart Then
  code "g1 z" & R	' Drill slowly down to first R value
  ZLast=R		' Last Z position
else
  ZLast=ZStart		' No movement as already there
end if

'Cycle control
ZTravel=ZLast-ZEnd		' Takes into account R<ZStart
ZCycles=int(ZTravel/Q)+1	' Number of cycles
ZIncr=ZTravel/Zcycles		' Actual Z increment to be used

'Cycle sanity check
if ZCycles> 300 then
'  MsgBox("More than 300 cycles",16,"Sanity Check")
  MsgBox("More than 300 cycles")
  stop
end if

For I = 1 to ZCycles
  ZTemp=ZLast+ZClear		' Just above contact
  Code "G00 Z" & Ztemp		' Rapid to start
  ZNext=ZLast-ZIncr		' Next peck down
  Code "G01 Z" & ZNext		' Drill next peck distance

  If C = 1 Then			' Select retraction mode
    Code "G00 Z" & ZLast	' G83.1 for fast/partial extract
  Else
    Code "G00 Z" & R		' G83 for full retract
  End If

  ZLast = ZNext			'Log new Z position
Next I

If ExitMode = 1 Then		' And where does ExitMode come from ????
  Code "G00 Z" & ZStart
else
  Code "G00 Z" & R
End If

If Test = True Then
  CloseTeachFile()
End If