How to reset Z offsets when using Manual Tool Change + length offset code

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09 May 2020 20:40 #167172 by Stephanisk
O<tool-change> SUB
( Filename: tool-change.ngc )
( LinuxCNC Manual Tool-Change Subroutines for Milling Machines version 1.1: subroutine 1/2 )
(  BEFORE USING CHANGE "CONFIGURATION PARAMETERS" BELOW FOR YOUR MACHINE! )
(  )
( In the LinuxCNC .ini config file, under the [RS274NGC] section add: )
(    # change/add/use SUBROUTINE_PATH to point to the location where these tool-change subroutines are located: )
(    SUBROUTINE_PATH = /home/linuxcnc/linuxcnc/nc_files )
(    REMAP=M6    modalgroup=6 ngc=tool-change )
(    REMAP=M600  modalgroup=6 ngc=tool-job-begin )
( and under the [EMCIO] section add: )
(    TOOL_CHANGE_AT_G30 = 0 )
( and ensure neither TOOL_CHANGE_POSITION nor TOOL_CHANGE_QUILL_UP is set. )
(  )
( In the LinuxCNC .hal config file, map some input pin to be the probe input, e.g.: )
(    net probe-z parport.0.pin-12-in => motion.probe-input )
(  )
( Usage: M6 in the g-code will invoke a manual tool change with automatic tool height adjustment. )
(        M600 is used at the beginning of the first g-code file of a job so that the next M6 will measure the tool for reference )
(             instead of caluculating a tool length offset. It can also be invoked manually through the MDI before a job starts. )
(  )
( General theory of operation: touches each tool off to the tool height sensor. The first tool is used as the reference, all )
(     subsequent tools adjust the tool offset. The tip of the tool is always placed back at the position it started in before )
(     any of the subroutines are called. It is moved away by raising Z to _TravelZ before moving towards the switch, and when )
(     moving back from the switch again moves at height _TravelZ before going straight back down to the original position. Set )
(     all necessary modes to ensure correct operation no matter what state the program is in when this is called. We eliminate )
(     almost all side effects by saving and restoring the modal state. )
(  )
( Side effects: sets G30, sets motion mode to G1. )

(------------------------------- CONFIGURATION PARAMETERS ----------------------------------------------)
#<_UseInches> =           0     ( set to 1 to use inches here, or 0 to use millimeters; should match units on tool.tbl dimensions )
#<_TravelZ> =          41.0     ( machine Z coordinate for travelling, typically near max Z to avoid ever hitting the work )
#<_TravelFeed> =     1000.0     ( feedrate used for general Z moves when avoiding G0 )
#<_ProbeX> =          145.0     ( machine X coordinate of switch/touch-off plate )
#<_ProbeY> =            0.0     ( machine Y coordinate of switch/touch-off plate )
#<_ProbeFastZ> =        5.0     ( machine Z coord to move to before starting probe, longest tool should not touch switch at this Z )
#<_ProbeMinZ> =       -37.0     ( machine Z coord to stop probe, shortest tool must touch switch at this Z, must be > min Z )
#<_ProbeRetract> =      1.5     ( small distance to retract before approaching switch/touch-off plate second time )
#<_ProbeFastFeed> =   400.0     ( feed rate for moving to _ProbeFastZ )
#<_ProbeFeed1> =       80.0     ( feed rate for touching switch/touch-off plate first time )
#<_ProbeFeed2> =       10.0     ( feed rate for touching switch/touch-off plate second time )
#<_ToolChangeX> =       0.0     ( machine X coordinate to pause at for manual tool changing )
#<_ToolChangeY> =     -50.0     ( machine Y coordinate to pause at for manual tool changing )
#<_MistOnDuringProbe> =   1     ( set to 1 for mist, or 2 for coolant, or 0 for nothing during probing, to clear switch of swarf )
(-------------------------------------------------------------------------------------------------------)

O100 IF [ EXISTS[#<_ToolDidFirst>] EQ 0 ]
        #<_ToolDidFirst> = 0
O100 ENDIF
O105 IF [ #<_ToolDidFirst> EQ 0 ]
   G49                                         ( clear tool length compensation prior to saving state if this is first time )
O105 ENDIF

M6                                             ( do the normal M6 stuff )
M70                                            ( save current modal state )

M9                                             ( turn off coolant, will be restored on return if it was on )
M5                                             ( turn off spindle, cannot be on during the probe )
G[21 - #<_UseInches>]                          ( use inches or millimeters as required here, units will be restored on return )
G30.1                                          ( save current position in #5181-#5183... )
G49                                            ( clear tool length compensation )
G90                                            ( use absolute positioning here )
G94                                            ( use feedrate in units/min )
G40                                            ( turn cutter radius compensation off here )

O200 IF [ #<_ToolDidFirst> EQ 0 ]
  G53 G1 F[#<_TravelFeed>] Z[#<_TravelZ>]      ( go to high travel level on Z )
  G53 G0 X[#<_ProbeX>] Y[#<_ProbeY>]           ( to probe switch )
  G53 G1 F[#<_ProbeFastFeed>] Z[#<_ProbeFastZ>]( move tool closer to switch -- we shouldn't hit it )
  G54 G1 F[#<_ProbeFeed1>] G91                 ( use relative positioning )
  O101 IF [ #<_MistOnDuringProbe> EQ 1 OR #<_MistOnDuringProbe> EQ 2 ]
    M[7 + #<_MistOnDuringProbe> - 1]           ( turn on mist/coolant )
  O101 ENDIF
  G38.2 Z[#<_ProbeMinZ> - #<_ProbeFastZ>] F[#<_ProbeFeed1>]    ( trip switch slowly )
  G0 Z[#<_ProbeRetract>]                       ( go up slightly )
  G38.2 Z[#<_ProbeRetract>*-1.25] F[#<_ProbeFeed2>]   ( trip switch very slowly )
  M9                                           ( turn off mist )
  G90                                          ( use absolute positioning )
  #<_ToolZRef> = #5063                         ( save trip point )
  #<_ToolZLast> = #<_ToolZRef>                 ( save last tool Z position )
  G53 G1 F[#<_TravelFeed>] Z[#<_TravelZ>]      ( return to safe level )
  G53 G0 X[#5181] Y[#5182]                     ( return to where we were in X Y)
  G53 G1 F[#<_TravelFeed>] Z[#5183]            ( return to where we were in Z )
  M72                                          ( restore modal state )
  #<_ToolDidFirst> = 1                         ( we have been in this section to set reference value already )
O200 ELSE
  G53 G1 F[#<_TravelFeed>] Z[#<_TravelZ>]      ( go to high travel level on Z )
  G53 G0 X[#<_ToolChangeX>] Y[#<_ToolChangeY>] ( nice place for changing tool )
  O107 IF [#<_UseInches> EQ 1 ]
    #<ToolDiamIn> = #5410
    #<ToolDiamMM> = [ #<ToolDiamIn> * 25.4 ]
  O107 ELSE
    #<ToolDiamMM> = #5410
    #<ToolDiamIn> = [ #<ToolDiamMM> / 25.4 ]
  O107 ENDIF
  O102 IF [ #<_current_tool> EQ 0 AND #<ToolDiamIn> EQ 0 ]
    (MSG, Change tool then click Resume )
  O102 ELSE
    #<ToolDiamMM> = [ #<ToolDiamIn> * 25.4 ]
    (DEBUG, Change to tool #<_current_tool> with diameter #<ToolDiamMM>mm, #<ToolDiamIn>in then click Resume )
  O102 ENDIF
  M0                                           ( pause execution )
 
  G53 G0 X[#<_ProbeX>] Y[#<_ProbeY>]           ( to high place directly over switch )
  G53 G1 F[#<_ProbeFastFeed>] Z[#<_ProbeFastZ>]( move tool closer to switch -- we shouldn't hit it )
  G54 G1 F[#<_ProbeFeed1>] G91                 ( use relative positioning )
  O103 IF [ #<_MistOnDuringProbe> EQ 1 OR #<_MistOnDuringProbe> EQ 2 ]
    M[7 + #<_MistOnDuringProbe> - 1]           ( turn on mist/coolant )
  O103 ENDIF
  G38.2 Z[#<_ProbeMinZ> - #<_ProbeFastZ>] F[#<_ProbeFeed1>]     ( trip switch slowly )
  G0 Z[#<_ProbeRetract>]                       ( go up slightly )
  G38.2 Z[#<_ProbeRetract>*-1.25] F[#<_ProbeFeed2>]   ( trip switch very slowly )
  M9                                           ( turn off mist )
  G90                                          ( use absolute positioning )
  #<_ToolZ> = #5063                            ( save new tool length )
  G43.1 Z[#<_ToolZ> - #<_ToolZRef>]            ( set new tool length Z offset, we do this now to show operator even though it has to be set again after M72 )
  G53 G1 F[#<_TravelFeed>] Z[#<_TravelZ>]      ( return to high travel level )
  G53 G0 X[#5181] Y[#5182]                     ( return to where we were in X Y)
  G53 G1 F[#<_TravelFeed>] Z[#5183 - #<_ToolZLast> + #<_ToolZ>]   ( return to where we were in Z, ajusting for tool length change )
  #<_ToolZLast> = #<_ToolZ>                    ( save last tool length )
  
  M72                                          ( restore modal state )
  G43.1 Z[#<_ToolZ> - #<_ToolZRef>]            ( set new tool length Z offset )
O200 ENDIF

O<tool-change> ENDSUB
M2

Hi,

This is the code i am using to do my toolchanges. This program works like a charm. Thanks to all developers!!!

I do have a question for enhancing the use of this code:

The problem i face is that after you have used the M6 code and are working let's say with an 18mm plate and you want to change to a 30mm plate ( keep in mind the Z0 point is set at the top of the plate), i have to completely power down the machine, reset all values in linuxcnc.var to 0 ( 5183 and 5223 ) , restart linuxcnc and than set the Z0 on top of the 30mm plate and run my code at which point the code will take my first tooloffset again and all will be fine.

If you don't reset all values to 0 than linuxcnc is thinking that the Z0 point still remains on the 18mm plate and when start milling on a 30mm thick plate, you can imagine what happens. It doesn't go so well :)

If i follow this way of working i can work with different sizes of plates and use the M6-M600 code perfectly. So i am very happy with this.

However: Is there a way to reset all stored values through an o subroutine, so i don't have to power down the entire machine and linuxcnc and manually start working in this linuxcnc.var file. It would be an enourmous time saver.

Hope someone has an answer to this. I came up with the idea to do the following which will reset all to 0 in linuxcnc.var but i have the impression that the stored offsets for Z height are in #5063 or something.
o<setzto0> sub

#5183 = 0
#5223 = 0

o<setzto0> endsub

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10 May 2020 12:03 #167257 by MaHa
Did you try already, if you set the named parameter '#<_ToolDidFirst>' to zero, in MDI or at the top of the program, where Z level is different '#<_ToolDidFirst>=0'. Then the section 'O200 IF [ #<_ToolDidFirst> EQ 0 ]' will run again.

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11 May 2020 02:56 #167322 by Stephanisk
I have always wondered where these parameters like #<_ToolDidFirst> are stored. If I knew that I might try to manipulate these values.

But if I get this pareter to 0, will it automatically reset all things to 0 or is a G49 command in the current state enough to clear all height offsets? (But than it would be without refZpoint.) So than set parameter to 0 and a G49 to clear all offsets in the current modal state.

So how do write this in a subroutine?

Thanks

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20 May 2020 17:17 #168392 by Stephanisk
Thanks so much for your help. It worked indeed as you proposed.

setting the #<_ToolDidFirst> to 0 does exactly what i need to happen.

Thanks again

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