--[[ 
AUTO TOOL ZERO FUNCTION
Author: GB Ward, Create! 2015
Rev: 0.1
Date: 4/25/15
Mach4 4.0.1, Build 2336

License: 
Public Domain

References:
Mach4 Core API Version 1.01 (C:\Mach4Hobby\Docs\Mach4CoreAPI.chm)

Mach4 CNC Controller Lua Scripting Guide
Newfangled Solutions 2014
http://www.machsupport.com/wp-content/uploads/2014/05/Mach4%20Scripting%20Manual.pdf

"Motion plugin probing procedure." (C:\Mach4Hobby\Docs\probing.txt)

Down and Dirty "mcLua scripting, quick ref guide"
poppabear, Mach4 English Forums, under "Mach4 Toolbox" board.

Pound Var List - poppabear, Mach4 Forums
http://www.machsupport.com/forum/index.php?action=dlattach;topic=27396.0;attach=38035

McLua mc scripting reference - poppabear, Mach4 Forums
http://www.machsupport.com/forum/index.php?action=dlattach;topic=27141.0;attach=37937

]]

function m10()

    local mInst = 0;                                        --Sets current controller instance to 0, if running multiple controller instances, this will need to change
    local rc = 0;                                           --Clear rc
    local hSig = 0;                                         --Clear hSig
    local inst = mc.mcGetInstance(mInst);                   --Captures current instance of Mach 4

    --SETUP OF VARIABLES
    local probe = mc.ISIG_PROBE;                            --Set input here, mc.<INPUT_NAME>; input needs to be mapped in Mach4
    local strikePlateThickness = 0.060;                     --What is the thickness of the strikeplate, or how much do you want to offset 0?

    --Function to check to see if probe already grounded
    function checkProbe ()

        hSig, rc = mc.mcSignalGetHandle(inst, probe);       --Load hReg with probe state
        state = mc.mcSignalGetState(hSig);                  --Get Signal State
        if (state == 1) then                                --if hReg true ('if probe is activated then')
            return true
        else
            return false
        end 
    end  --checkProbe()

    --BEGIN
    --Get current Feed rate, G90/G91, G0/G1 states to return to later.
    --Mach4 stores these variables as 'Pound Variables'
    --See Mach4 Lua Scripting Manual Page 23
    local CurrFeedRate = mc.mcCntlGetPoundVar(inst, 2134);              --Gets current Feed Rate, #var 2134
    local CurrFeedMode = mc.mcCntlGetPoundVar(inst, 4001);              --Gets current G0/G1 state, #var 4001
    local CurrPositionMode = mc.mcCntlGetPoundVar(inst, 4003);          --Gets current G90/G91 state, #var 4003
    local zProbeStrikePos = 0;                                          --clear variable
    
    if checkProbe() then                                                --Check probe status
        mc.mcCntlSetLastError(inst, "ERROR: Probe is already triggered.  Cannot continue.");
        do return end                                                   --"do return end" stops program.  Not sure how this works 
    end --check if probe is grounded

    mc.mcAxisSetPos(inst, 2, 0);                                        --"Zero Z" (0 is x, 1 y, and so on)
    mc.mcCntlGcodeExecuteWait(inst, 'G01 G90 G31 Z-4 F4');              --G31.  Machine will stop on probe strike or go to Z-4, store in #var 5063
    local zProbeStrikePos = mc.mcCntlGetPoundVar(inst, 5063);           --Get Z strike position
    local zAxisCurrentPos = mc.mcAxisGetPos(inst, 2);                   --Get Current Z position, sometimes the probe will continue past strike point.
    local zAxisDifference = (zProbeStrikePos - ZAxisCurrentPos);        --Gets overshoot, returns positive
    local zAxisNewOffset = strikePlateThickness - zAxisDifference;      --Subracts overshoot from known thickness of strikeplate
    mc.mcAxisSetPos(inst, 2, zAxisNewOffset);                           --Sets DRO to current position 
    --mc.mcAxisSetMachinePos(inst, 2, zAxisNewOffset);                  --Sets Machine to offset if anyone finds this necessary
    mc.mcCntlGcodeExecuteWait(inst, 'G00 G91 Z1');                      --Rapid move to 1 inch above current pos

    local isProbeSafe = checkProbe();                                   --Checks to see if probe is safe
    if isProbeSafe == true then
        wx.wxMessageBox("Probe is still activated!  Check to make sure probe is not damaged or still contacting strike plate.");
    else
        mc.mcCntlSetLastError(inst, "Z Axis now referenced.");
    end --if

end --main



if (mc.mcInEditor() == 1) then
    m10()
end