Need Help!!!

I am trying to send a signal from a PC parallel port into an Allen Bradley relay input so I can have the bit close and turn on my output to turn on another cpu(school project ). Is this possible and if so how do I do it.

I tried stripping a printer cable and using the 8 data pins and hooking them to an input. I even attempted to write a code in linux to send 255 through the printer cable to the PLC input but of course no luck. Is there an easier way?

You have to be kidding

I dont mean to sound harsh BUT I am going to.

Did you make any attempt to STUDY? ANY attempt to learn how AB plc's communicate? How they work?

HAVE you done anything but ask this question?

I am trying to send a signal from a PC parallel port into an Allen Bradley relay input so I can have the bit close and turn on my output to turn on another cpu(school project ).

Click to expand...

You have to be kidding.

NOTE: This can be done but as I stated above...have you READ anything? Personally not sure WHY anyone would do it this way though.

A few problems:
1, printer ports generally work on 5V signals, PLC relay inputs generally work on 24V or 110V or 240V. You should therefore use some sort of amplifier and/or isolation.
2, are you actually getting any output from your printer cable at all?
I would suggest you wire the pins through some LEDs and see if you can make these come on. If not, forget about interfacing with the PLC until you can get these to come on.

Another tip, Interfacing with the printer port for control of I/O is a favorite topic among hobby type automators. I have a book picked up for $5 on how to do this, and I believe there are quite a few web sites on how to do this. There are a few tips needed to get these things to work, but I can't recall what they are off the top of my head.

Good luck with your project.

Doug

Well, it's weird, but that doesn't mean you shouldn't try it. I hope that you have some fundamental electrical knowledge as well as Linux skills.

What model of A-B input module are you working with ? That part number will let you determine what voltage you need to supply.

I just tossed an old ElectroCam solid-state relay that would be ideal for this... I'll go see if it made it out to the curb.

rsdoran

Exscuse me if I am just now learning about PLC's in my class. Not everybody can be an expert. Don't mean to sound rude.

Here's a link as a starter for the PC parallel port side Parallel Port

Port proggy

Here is a little utility to switch states on the port. May help but you will still need SOME type of solid state relay or other device to switch your INPUT voltage to the PLC. Be careful of port having its common (somewould call it ground and the device having another common (diff in potential could be lethal to the port).