Remote Machine Stop Interfacing

[Redline99]

Hi, I have project and yeah I'm total beginner here so having someone look over or make suggestion would be very appreciated.

The project is that I have to pull to ground a remote machine stop.  The device I have under my control from a computer is a USB solid state pnp FET "switch".  (ACCESS IDIO-4).   Attached is a simplified wiring diagram with how I think best to get this going, remember I'm a beginner here so I am probably completely wrong.  The parts encompassed in a dotted boxes are outside my control.  My main dilemma is that I need to pull to ground the remote stop using a P-Channel device.  I think I can only do that by adding a N-Channel to the circuit?  Is there a way to do this without a N-Channel to accompany the USB IO device?

Thank you for any help and suggestions!

[danadak]

Your solution seems logical. Just insure when P channel is on
the Vgs of the Nchannel turns it on adequately. Also the N channel
turn off speed is constrained by the Pchan pull down, but if this
is a "light switch" type of application, ie. the speed you need to turn
off, you are probably ok. Note also as MOSFET turns off slowly it
will experience increased Pdiss due to time it spends in active region.
So think in terms of 100's of ohms for P chan pulldown. You can always
spice the tunr off to see what effects your Pchan pulldown has.

Also consider noise effects from turning off large L loads in the vicinity
of the circuit. Choose a FET with appropriate breakdown V, maybe
diode protect gate of Nchan with zeners if you find a lot of noise in
the circuit environment.

Regards, Dana.

[Redline99]

Thank you Dana that is very good information for me.

And just to be sure, am I correct that there is not a simpler method of interfacing without using the N-Channel component?