may have made the wrong choice @#$%%$###!!!

My machine went down TEN MONTHS AGO. I went with mach 3 for my pc conversion. Bought dugong drives. Cnc4pc breakout boards, encoders. Took forever to figure out the wiring because of poor documentation. Finally had it running correct distance one axis at a time but when I ran two at a time it way overtravelled and didn't show any encoder error message. Pc hard drive crashed. Now I have a different pc but I doubt it will fix the overtravel issue. Hindsight stinks.

My apologies andy. My plans for this project is to keep fighting with it. Lol. My next project may go a different direction.

Like Andy says this really sounds like a wiring error in the step/dir signals.
Perhaps a missing ground between the PC/breakout and one or more of the drives.
I would try again by jogging each axis carefully and checking that the other axis do not move.

What kind of cabling are you using for your signalling? Is it twisted pair? Shielded? Are you sending the signals from multiple joints through a shared cable? I would suggest investing in a simple usb scope and reading whats coming out of the other end of the cables. Anytime you (or I or anyone else )are working on electronics without some kind of signal visualization (even a cheap usb PC o-scope is more than enough 99% of the time) you are working by making stabs in the dark. Its kind of like watching those discovery channel shows with the orangutangs solving problems by poking holes with twigs.

Taking your problem apart purely from the limited description:

One joint works by itself.

Does the other joint also work by itself?

When both joints run together does one or two joints over-run? If both over-run, do they over-run by the same amount? This would be a gimmie for cable pair cross talk. (Cheap cables? Bad ground and retro feed? Is the cable shield grounded properly?)

This is probably a very simple problem, its just a question of going through the usual suspects first and then moving to the more complicated probable causes.

Frank

dangercraft wrote:This is probably a very simple problem, its just a question of going through the usual suspects first and then moving to the more complicated probable causes.Frank[/quote]

The problem turned out to be incompatibility between the CNC4PC board and the Dugong HDBB board, which Brad had connected in series. Once he removed the CNC4PC board the problem went away. Last time I talked to him he was making good parts.

Doug