I have a 6 position turret toolchanger on an old lathe (pokeys57cnc retrofit) that takes a PWM signal for motor speed and IO signal for changing tools and/or locking the turret.
It also has 6 hall sensors on the back for sensing current tool and a sensor for ensuring the turret is in lock. This will be used for changing tools automatically.
I have a custom m6.mcs script in the macro folder of the lathe profile. 
Whenever I hit cycle start using any combination of TX M6 Mach4 starts doing the original manual m6.mcs that was in that folder.
Renaming/deleting the old macro didn't seem to delete it?

I don't have access to the up to date script but it looks something like the below.
Ignore how I'm handling turning the motor on I've fixed that.

function m6()
local nTools = 6
local turretMove = false
local turretLock = false
local inst = mc.mcGetInstance()
local selectedTool = mc.mcToolGetSelected(inst)
selectedTool = math.tointeger(selectedTool)
local currentTool = mc.mcToolGetCurrent(inst)
currentTool = math.tointeger(currentTool)

--map an array of tool turret position signals to tool numbers
local Tools = {
        [1] = mc.ISIG_INPUT1,
        [2] = mc.ISIG_INPUT2,
        [3] = mc.ISIG_INPUT3,
        [4] = mc.ISIG_INPUT4,
        [5] = mc.ISIG_INPUT5,
        [6] = mc.ISIG_INPUT6}

--if selected tool is invalid msg and exit
if (selectedTool>nTools) or (selectedTool<1) then
return "Tool Number out of range", false
end
--if tool is the same do nothing just exit
if selectedTool == currentTool then
return false
end
--Check if turret is locked if not msg and exit
turretLock = GetSignal(mc.ISIG_INPUT0) --gets lock signal
if turretLock == 1 then
return "Turret may not be locking properly", false
end
--Remove this line if you would not like the Z axis to move
--mc.mcCntlGcodeExecute(inst, "G90 G53 G0 Z400");--Move the Z axis to 400 out of the way

--Go forward until tool sensor input matches selectedTool
WriteSignal(mc.OSIG_OUTPUT0, 0) --Set direction to move turret
WriteSignal(mc.OSIG_OUTPUT7, 0.77) -- Set motor output PWM level ie turn motor on
turretMove = true
while (turretMove == true) do
local toolSig={}; --empty array for storing signal values
--Grab all the states of the turret sensors
for i=1,nTools,1 do
toolSig[i] = GetSignal(Tools[i])
end
--Check if the turret sensor we want has triggered
--if so turn off motor
if toolSig[selectedTool] == 0 then
WriteSignal(mc.OSIG_OUTPUT7, 0) -- turn off motor
turretMove = false
end
end
--lock turret in place and check locked
WriteSignal(mc.OSIG_OUTPUT0, 1) --Set direction to lock turret
WriteSignal(mc.OSIG_OUTPUT7, 0.77) -- Set motor output PWM level ie turn motor on
turretMove = true
while (turretMove == true) do
turretLock = GetSignal(mc.ISIG_INPUT0) --get lock signal
if turretLock == true then
WriteSignal(mc.OSIG_OUTPUT7, 0) --turn off motor
turretMove = false
end
end
mc.mcToolSetCurrent(inst, selectedTool) --set current tool
end


Mach4 Lathe uses T0101 NOT T1 M6

Thanks Graham that was one part. The other was adding M30 to the MDI so it didn't loop.
One other thing I did wrong was creating custom functions GetSignal() etc. in the screen load script.
I tried to use these in the m6() function but they couldn't be run unless I added them to the start of the m6.mcs.
I incorrectly assumed these could be declared in the screen load script and called in a macro.
I'll post the final code here for others when I get back to the workshop next week.

  Have you got the solution for your Problem ?