Well this is my senario...I recently bought a 4x4 Pro-Cut plasma table .And i bought it off a a guy that was the second owner that never used it ,and he bought it of a family that was selling there fathers stuff after he passed away.So i have no history of this machine being used or modified  .So anyways i  took it home got all motors working through mach 3 .So this is a 2 axis system with a manual torch height adjustment . The controller is a Sound Logic pc-2 route breakoutboard with gecko drivers.

  Here is the PROBLEM how do i get mach to control the torch as far as turn on when it sould be cutting and off when it sould not be cutting.The  bob has many  outputs  that are  12v .So  far i got my plasma hooked up internally with 2 wires and i will just use that 12 v signal of the bob to energize a 12v  relay to turn the plasma on.

  So what  output can i uses in mach 3 to control the torch, i know i can use an output to control  a coolant pump but there is only really an input section for thc on on Mach3
Thanks

Not knowing what pins and such are being used on your breakout board, I can only give you a general setup that is simple but the pin numbers will have to be determined by you. In the ports and pins config section, look at spindle output. Normally pin #1 is set for CW and CCW spindle output. That will turn pin #1 on when you turn the torch(spindle) on. This pin is where you energize your relay for plasma start. Next, go to general config and set the input #1 option on. This prevents machine motion until your plasma transfers an arc. Input #1 will stop all progress if input #1 is active or high. That allows you to hook up a current sensor (reed switch or current relay) to input #1 and make the machine wait for a good arc. This may be already built in to your plasma power supply. Input #1 will need to be run through the relay that turns your plasma on as you do not want it to stop the machine when the plasma is not energized. You can forget about input #1 setup if you don't need the "arc OK" option.  More info on your plasma brand and model would help.