There are many possible ways to utilize the e-stop and fault circuits, and even
more is you are ganging two cards. Without knowing the wiring and jumper
settings in you machine, it is difficult to offer usable advice.
The PMDX-122 will present E-Stop/Fault* status on pin 10 of the parallel
port as an active high signal.
The E-Stop input is activated when driven high, or when it is open circuit.
Normal operation requires the input to be connected to ground or driven
low.
The Fault* input is activated when the signal is driven low. If there is no wire
connected to the Fault/ terminal, the board will run normally. The E-Stop
input will override the Fault/ input, so you must ground the E-Stop input
if you want to be able to use the Fault* input by itself.
It is possible to daisy chain the fault logic between two boards, and use
the E-Stop input of the second board as a general purpose signal. To do
this see page 29 of the users manual here:
http://www.pmdx.com/Doc/PMDX-122_Manual_112.pdfThis shows the required interconnection and jumper settings.