Hi all,

I've been using mach3 with an XP computer with one parallel port running a 3 axis mill. Works great for me. I wanted to add a second parallel card for more inputs and a MPG. I popped in a pci parallel port card that came with proper drivers for win 2000, XP, etc. Problem is when I enable the second port, even with all port pins disabled, my max pulse train going out to the motors is quite unstable. Low speed motion seems OK but high speed is very bad. When port 2 is disabled, the problem is gone (the card is still installed).

kernel is set to 25 kHz, max motor pulse frequency is 13.3 kHz. Dell Optiflex 1GB ram, 3 MHz processor, I've tried faster kernel frequencies but no change in the issue.

I bought the pci parallel card at Office Depot, I don't know the brand but I can pop the hood to get that info if it makes any difference.

Any ideas or suggestions to fix this would be most welcome. The other option is to go with MODBUS but the cards I've seen for MODBUS are expensive, I just need inputs for a nice MPG like what's for sale at CNC4PC.

Thanks for your time!

Another option is the PoKeys for more I/O.
Hood

Dell Optiplex ....hmm .........I have tried using a GX520 and can only say do not use with a PP.
Fine PC for anything other than CNC.

RICH