Lack of pins on parallel port. Replace estop?

we got more then 5 Plasmas in use
all beside one build by the desesed Member here
and noone has a Arc-ok signal wire
it workes that way
IF the Torch does not fire (( hapens not offen on a 85A))
you will HEAR it quickly in the display where to restart NO problem

if the Arc goes/dies down as to many Water in the Nozzel during CUT
You can restart from last in Point OR manipulate the Gcode as you see the outpoint on Manuell jog
THIS Happens only on USER Fault / Meaning wrong settings
Nozzel to the Max livetime / Overcut speed / EP Time of the Cutter between Cuts

Another way you could use a pin for more than one purpose is to set a pin using M62-M65 in gcode and connect that output pin to a MUX2 to swap pin signals on that command. You might be able to use this when probing for instance.

It would be interesting to see you could use the plasmac config with your THC. So far most people have been using a mesa THCAD board but it has a mode to support your style of THC. Whilst this requires a recompile to include the reverse run branch that is not yet in Linuxcnc master branch, you could run your existing mill subject to the usual changes required to move from V 2.7 to V 2.8 for independent axes and multi spindle support.

It looks like too much work. Unfortunately I don't have time nor much of a desire to do all that

Most plasmas will need the arcok true for the entire cut or they will think the torch has gone out.

I'm developing a custom THC so it may or may not need anything

How about 2 pins:
1 = Up
2 = Down
1 + 2 = Arc OK
No pins = something bad happened.

Sounds good. Could you please elaborate on how can I hook it up in my hal file?
I only have 2 days left to set this thing up and I think I won't be able to read thru all the docs and understand everything correctly.
I think I need to use some AND logic to get signal from 2 pins at a time

caseyryan wrote:

How about 2 pins:
1 = Up
2 = Down
1 + 2 = Arc OK
No pins = something bad happened.

Sounds good. Could you please elaborate on how can I hook it up in my hal file?

Assuming that you can generate the input combinations the HAL side of things would use "demux"
linuxcnc.org/docs/devel/html/man/man9/demux.9.html [1]
Then assuming parport.0.pin-00-in is the UP signal, and 01-in is DOWN and both is ARC-OK

[1]Which doesn't exist in 2.7, I just noticed, but it is a simple .comp and can be downlaoded the compiled/installed with halcompile)
Download this file , save as "demux.comp"
Then use the command "sudo halcompile --install demux.comp" to install it on your system.

@ andy
dipending on the THC in use
this will nor work as ther can be Arc-ok Faults on settings like from proma
it might be flickering so it stopt the mashine on arc ok

here arc ok is not connected at all and on normal part use it is not needed

Parallel port has 3 distinct working modes, the usual "out" that does 12 outputs and 5 inputs, the "in" that does 13 inputs and 4 outputs ( data pins D0 to D7 as inputs ), and the rarely mentioned "X" mode that does 8 outputs and 9 inputs.
So if you do not need all 12 outputs, set it to mode X and enjoy additional 4 inputs on pins 1,14,16,17.
In hal change
Loadrt ..........0x378 out <<or whatever the address is, replace "out" with "X" and test.
Not all parallel port can use that mode, all built in I have tested do work and all the PCI parallel cards I had with MosTech chips do work.