function m6()

--Non-Random automatic tool changer
--This file assumes that you have G54 X0 Y0 Z0 to be setup as the Y-offset distance from tools and the correct height for picking
--up/dropping a tool as well as the correct X location for entering the tool changer.


----------Variables----------
local inst = mc.mcGetInstance() --Get the instance of Mach4

local hReg = 0

local ToolInColletSig = mc.ISIG_INPUT0 --These outputs/inputs will be configured by the user depending what outputs/inputs they have setup in Mach config.
local MotorSig = mc.OSIG_OUTPUT0
local CloseColletSig = mc.OSIG_OUTPUT1

local CurrentTool = mc.mcToolGetCurrent(inst)
local NextTool = mc.mcToolGetSelected(inst)
local YOffsetDistance = 14.25------------DEFINE Y OFFSET DISTANCE 
local numtools = 4
local ToolPositionIO = {}
-----------------------------
function ToolChange(NextTool)
	--------------------------INPUT CHECKING-----------------------------
	if (NextTool > numtools) then
		return "That tool does not exist", false
	end
	
	hReg = 0 --reset hReg to 0 each time before reading it so you know if you get an error. 
	hReg = mc.mcIoGetHandle(inst, ToolInColletSig)
	if hReg == 0 then
		return "Could not locate tool in collet signal!", false
	end
	
	hReg = 0
	hReg = mc.mcIoGetHandle(inst, MotorSig)
	if hReg == 0 then
		return "Could not locate motor signal!", false
	end
	
	for i = 1, numtools+1 do
		ToolPositionIO[i] = 0
		ToolPositionIO[i] = mc.mcIoGetHandle(inst, "Position"..tostring(i))
		if ToolPositionIO[i] == 0 then
			return "Could not locate tool position signal!", false
        end
	end
	
	hReg = mc.mcIoGetHandle(inst, CloseColletSig)
	if hReg == 0 then
		return "Could not locate collet close signal!", false
	end
	----------------------END INPUT CHECKING-----------------------------
	
	local rc = mc.mcIoGetState(ChuckhReg)
	if rc == 1 then --If rc equals 1, then there is a tool in the chuck
		--Put the tool away.
		rc = mcCntlGCodeExecuteWait(inst, "G54 X0 Y0 Z0") --Move to the offset zone.
		if rc ~= mc.MERROR_NOERROR then return "Could not complete GCode motion", false end
		--We are now at the offset line, and need to move the correct Y Distance so we can drop off the tool.
		mcCntlGCodeExecuteWait(inst, "G91 Y"..YOffsetDistance)
		if rc ~= mc.MERROR_NOERROR then return "Could not complete GCode motion", false end
		
		hReg = 0
		hReg = mc.mcIoGetHandle(inst, CloseColletSig)
		if hReg == 0 then
			return "Could not locate close collet signal!", false
		end
		mc.mcIoSetState(hReg, 0) --Release the tool
		mcCntlGCodeExecuteWait(inst, "G54 X0 Y0 Z0")--Move back to the offset line
		if rc ~= mc.MERROR_NOERROR then return "Could not complete GCode motion", false end
	else
		mcCntlGCodeExecuteWait(inst, "G54 X0 Y0 Z0")--Move to the offset line
		if rc ~= mc.MERROR_NOERROR then return "Could not complete GCode motion", false end
	end
	
	--At this point, we are at the offset line, and there is no tool in the chuck.	
	hReg = 0
	hReg = mc.mcIoGetHandle(inst, MotorSig)
	if hReg == 0 then
		return "Could not locate motor signal!", false
	end
	mc.mcIoSetState(hReg, 1) --Turn on the motor until we are at the desired tool change position.
	
	local loop = true
	while(loop == true) do
		local a,b = mcIoGetState(ToolPositionIO[NextTool])
		if(b == true) then
			if(a == true) then
				loop = false	
				hReg = 0
				hReg = mc.mcIoGetHandle(inst, MotorSig)
				if hReg == 0 then
					return "Could not locate motor signal!", false
				end
				mc.mcIoSetState(hReg, 0)--the tool changer is now rotated to the correct location.
											 --so we turn off the motor.
			else
				wx.wxMilliSleep(100) --Sleep for 100 milliseconds, and then recheck input.
			end
		else
			hReg = 0
			hReg = mc.mcIoGetHandle(inst, MotorSig)
			if hReg == 0 then
				return "Could not locate motor signal!", false
			end
			mc.mcIoSetState(hReg, 0)
			return "Unable to get state of motor IO", false
		end
	end
	
	mcCntlGCodeExecuteWait(inst, "G91 Y"..YOffsetDistance) --Move into the tool changer
	if rc ~= mc.MERROR_NOERROR then return "Could not complete GCode motion", false end
	
	hReg = 0
	hReg = mc.mcIoGetHandle(inst, CloseColletSig)
	if hReg == 0 then
		return "Could not locate collet close signal!", false
	end
	mc.mcIoSetState(hReg, 1) --grab the tool.
	
	mcCntlGCodeExecuteWait(inst, "G54 X0 Y0 Z0")--Move back to the offset line
	if rc ~= mc.MERROR_NOERROR then return "Could not complete GCode motion", false end
	return "Tool change complete!", true
end

local a, b = ToolChange(NextTool)
mc.mcCntlSetLastError(tostring(a))--Prints status of tool change.
if(b == true) then
	mc.mcToolSetCurrent(inst, NextTool)
end

end
if (mc.mcInEditor() == 1) then
	dofile ("load_modules.mcs")
    m6()
end