I/O cards to interface

[widgitmaster]

Of all the routers I've built and wired up, the most frustrating part is running out of pins to attach extra devices. Now the LPT port is old school, and never designed to interface a complex CNC machine. To complicate things even more, the same LPT port is becoming obsolete!

Has anyone designed a better interface card, with more I/O connections?
Everyone has suggested using a USB pendant which has an MPG, remote Cycle Start, E-Stop, Pause, Jog buttons, etc..
But at the same time, I've heard that USB is not so good!

Has anyone used the "BLACK BOX" brand of I/O cards to interface a CNC to a PC?

Widgit

[H.O]

Hi Eric,
Depends on what you want to use the I/O for. If you want your step- and direction signals to be thru this I/O device then (and if we're talking Mach3) you have a couple of option (in no particular order and there may be others as well).

1) KFlop motion controler from Dynomtion (USB).
2) DSMPC from Vital Systems (I THINK it supports step and direction) (Ethernet)
3) Smoothstepper from Warp9 (USB)

These all have pros and cons so make sure to read up on each of them.

If you need "general I/O" ie everything except motion/home/limits/probe then there are several options. PoKeys55 is a nice and popular, highly configurable little device (USB). Another option is to use a MODBUS capable device, CUBLOC has small modules that talk MODBUS and a lot of industrial PLC's do MODBUS as well.

Another option is the PMDX-125. This is a breakoutboard for one or two LPT-ports that uses a Mach3 plugin and a special tecnique to multiplex more I/O's "on top" of the normal ones. Make sure to read up on how it works and what it provides in order to determine if it would work for your application.

Then, of course, you can always add a second LPT-port-card to the PC. Or, in case the PC lacks a port, add two cards.

Well, that's a couple of options for you to consider.

/Henrik.

[vger]

Hey Widgit,

Take a look at these guys http://www.mesanet.com/ and the "Anything I/O FPGA cards". I believe EMC2 has some plugins for a couple of these. You might also be interested in the "Motion Control" components they have.

Steve

[widgitmaster]

Thanks Guys!
I'm getting closer to a solution for the IO problem!
Widgit

[kineticstep]

The Teensy, which is a dev board for an Atmel uC that has USB support may be an option. It's currently in high demand for PS3 hacks, but there are similar ready-to-go boards around.

USB is not a bad protocol to communicate with the board, just don't rely on the timing of USB messages. Have your logic on the uC do the critical timing work, and manage your interrupts so it doesn't interfere.

There are also a few ARM boards that are really capable and cheap, though they are mostly 3V.