I tried to compare the code in the computer where I have the pantograph.
in that computer I have a Smooth Stepper Ethernet.
result:
the code works.
when Mach4 is fully loaded, M8 is deactivated.
the only drawback is that it gives an ignition pulse to the relay while Mach4 is charging, and this is not good.
so I assume it's a question of plugins.
are there any other alternative methods?
How can I connect the OFF status when I press E-STOP?
Can you give me an example, please?

As far as the ESS goes.  I've got several here in the shop and anytime Mach is not opened all of my outputs are turned on; I don't know why, but it happens and I deal with it.  I added a toggle switch to turn my relays off.
As far as the EStop signals.
Like I mentioned earlier, put it in the signal library.  Instead of it being an input# for the signal, find the E Stop Signal ID and put it there.

[mc.ISIG_EMERGENCY] = function (state)
    if (state == 1) then
              --Conditions
    end
 end, 

Chad

I had the output on do dah but only on the spindle a couple of relays sorted that out by cutting the power to the spindle until the ESS powered .

Thinking about it now I am thinking that’s its down to how the system is powered up

Mine has the ESS powered from a 5vdc in the mill therefore the come on together and that will be before the pc has the ESS under its wing

Theory

Mill off
Power ESS
Power pc and start mach4

Then turn on the mill

That way the mach4/ESS will be in a stable running condition before the mill on

Just a 2 cents of thinks

Stuart.  Not a bad way to do it, only I have all my power coming on at once from a button on the front of the machine.
This turns everything on at the same time.  Because of this, the relay switch I have works well.
Another way you could do it, and it sounds like something you have implemented, would be to use a charge pump.  That way until mach and the ESS are communicating the charge pump relay is open, then the relay could power the rest of the machine.

Chad

You can give the pencils out tomorrow for that deduction