```
(author: Chris P)
(version: 0.3)
(date: 04/22/19)

(Probe front left top corner for x,y,z 0,0,0 position)
(Start probe position is over front left corner of stock)
(inside the step off width square and within max z distance)
(ensure all settings have been set properly according to help diagrams)

o<probe_front_left_top_corner> sub

  (uses NGCGUI style arg spec)
  (number after "=" in comment is default value)
  #<probe_tool_number> = #1    (=99)
  #<max_z_distance> = #2       (=.5000)
  #<max_xy_distance> = #3      (=.5000)
  #<xy_clearance> = #4         (=.0000)
  #<z_clearance> = #5          (=.1000)
  #<step_off_width> = #6       (=0 what is this?)
  #<extra_probe_depth> = #7    (=0)
  #<probe_slow_fr> = #8        (=5)
  #<probe_fast_fr> = #9        (=20)
  #<calibration_offset> = #10  (=.0000)
  #<x_hint> = #11              (=0)
  #<y_hint> = #12              (=0)
  #<diameter_hint> = #13       (=.7500)
  #<edge_width> = #14          (=.5)

  (Cancel G92 offsets)
  G92.1

  #<workspace_x> = #[5201 + [20 * #5220]]
  #<workspace_y> = #[5202 + [20 * #5220]]
  #<workspace_z> = #[5203 + [20 * #5220]]

  (Probe Tool Safety Check)
  o<110> if [#5400 NE #<probe_tool_number>]
  (MSG, Specified probe tool #<probe_tool_number> not in spindle, aborting)
   o<probe_front_left_top_corner> return
  o<110> endif

  (Probe Diameter)
  #<probe_diameter> = #5410

  (Probe Radius)
  #<probe_radius> = [#<probe_diameter> / 2]

  (Probe Centerline Offset)
  #<probe_center_offset> = [#<probe_radius> - #<calibration_offset>]

  (Current Z Position including offsets in current program units)
  #<z> = #5422

  (Current Feed Rate)
  #<feed> = #<_feed>

  (Probe Top of Workpiece)
  G91

  (Initial Fast Z- Probe)
  F[#<probe_fast_fr>]
  G38.2 Z-[#<max_z_distance>]
  #<z_probe_fast> = #5063

  (Probe Error check, #5070 will be 0 if failed)
  o<120> if [#5070 EQ 0]
    (back to start point and feed)
    G90
    G0 Z#<z>
    F#<feed>
    (return from sub)
    o<probe_front_left_top_corner> return
  o<120> endif

  (Move to z_clearance height for slow probe)
  G90
  G0 Z[#<z_probe_fast> + #<z_clearance>]

  (Slow Probe Rule, if Slow Probe FR is set to 0, Slow Probe is Bypassed)
  o<130> if [#<probe_slow_fr> GT 0]
    (Initiate Slow Z- Probe)
    G91
    F[#<probe_slow_fr>]
    G38.2 Z-[#<z_clearance> * 2]
    #<z_probe_slow> = #5063
    (debug, Probed Pos: #5063 Z Pos: #<_z>)
    G90
    G0 Z[#<z_probe_slow> + #<z_clearance>]
  o<130> endif

  (Record Z zero in selected WCO)
  G10 L2 P#5220 Z[#5063 + #<workspace_z>]

  (Probe X Positioning Move, Step Off Width)
  G91
  G0 X-[#<step_off_width>]

  (Probe X Positioning Move, to Probing Depth)
  F[#<probe_fast_fr>]
  G1 Z-[#<z_clearance> + #<probe_diameter> + #<extra_probe_depth>]

  (Current X Position including offsets in current program units)
  #<x> = #5420

  (Initiate Fast X+ Probe)
  G38.2 X[#<max_xy_distance>]
  #<x_probe_fast> = #5061

  (Probe Error check, #5070 will be 0 if failed)
  o<140> if [#5070 EQ 0]
    (back to start point and feed)
    G90
    G0 X#<x>
    F#<feed>
    (return from sub)
    o<probe_front_left_top_corner> return
  o<140> endif

  (Move to xy_clearance distance for slow probe)
  G90
  G0 X[#<x_probe_fast> - #<xy_clearance>]

  (Slow Probe Rule, if Slow Probe FR is set to 0, Slow Probe is Bypassed)
  o<150> if [#<probe_slow_fr> GT 0]
    (Initiate Slow X+ Probe)
    G91
    F[#<probe_slow_fr>]
    G38.2 X[#<xy_clearance> * 2]
    #<x_probe_slow> = #5061
    (debug, Probed Pos: #5061 X Pos: #<_x>)
    G90
    G0 X[#<x_probe_slow> - #<xy_clearance>]
  o<150> endif

  (Record X Zero in selected WCO)
  G10 L2 P#5220 X[#5061 + #<workspace_x> + #<probe_center_offset>]

  (Probe Y Positioning Move, up to Z clearance plane)
  G91

  G0 Z[#<z_clearance> + #<probe_diameter> + #<extra_probe_depth>]

  (Probe Y Positioning Move, Traverse Workpiece Top at Z Clearance Height plane)
  G0 X[#<step_off_width>] Y-[#<step_off_width>]

  (Probe Y Positioning Move,to Probing Depth)
  F[#<probe_fast_fr>]
  G1 Z-[#<z_clearance> + #<probe_diameter> + #<extra_probe_depth>]

  (Current Y Position including offsets in current program units)
  #<x> = #5421

  (Initiate Fast Y+ Probe)
  G38.2 Y[#<max_xy_distance>]
  #<y_probe_fast> = #5062

  (Probe Error check, #5070 will be 0 if failed)
  o<160> if [#5070 EQ 0]
    (back to start point and feed)
    G90
    G0 Y#<y>
    F#<feed>
    (return from sub)
    o<probe_front_left_top_corner> return
  o<160> endif

  (Move to xy_clearance distance for slow probe)
  G90
  G0 Y[#<y_probe_fast> - #<xy_clearance>]

  (Slow Probe Rule, if Slow Probe FR is set to 0, Slow Probe is Bypassed)
  o<170> if [#<probe_slow_fr> GT 0]
    (Initiate Slow Y+ Probe)
    G91
    F[#<probe_slow_fr>]
    G38.2 Y[#<xy_clearance> * 2]
    #<y_probe_slow> = #5062
    (debug, Probed Pos: #5062 Y Pos: #<_y>)
    G90
    G0 Y[#<y_probe_slow> - #<xy_clearance>]
  o<170> endif

  (Record Y Zero in selected WCO)
  G10 L2 P#5220 Y[#5062 + #<workspace_y> + #<probe_center_offset>]

  (Probe Completion Move to Z Clearance Plane, and X Zero, Y Zero)
  G90
  G0 Z[#<z_clearance>]
  G0 X0.0000 Y0.0000

o<probe_front_left_top_corner> endsub

M02 (end program)