Thanks JH,
Basically what happens is the thing is rock solid. Then it will randomly have either an e-stop or limit switch trip. Once this starts up It usually doesn't calm down until I turn the machine off for a while. This doesn't always work and sometimes it's still flaky when I start it back up dead cold. Once the problem starts, I push the reset and it immediately trips. The DRO for spindle RPM starts jumping around also. So basically all the inputs start going haywire. If I then disconnect the spindle speed sensor from the board the BOB really starts going haywire with LED's and relays clicking away like Morse Code.
I've been through the whole machine. I've basically got it isolated to the breakout board. I can disconnect all the external wiring from the BOB to my machine except the power, and replace the E-stop and Limit SW with a jumper but the problem is still there. Even with all the 3 phase stuff completely disconnected from the wall. So it's not noisy wiring or a ground loop.
If I disconnect the printer cable at the BOB the problem goes away. I have also made a new printer cable and still have the problem. I really think it is a problem in the BOB.
I ALWAYS shield things and ground at one end. Also use a single point ground. Put snubbers on all the AC coils and diodes on the DC ones. Also run all AC lines separate from DC. I also try to separate all signal lines from stepper motor lines, but I couldn't do that to the turret. They are both shielded and routed in a shielded conduit. I've learned all that the hard way.
I have wondered if the Parallel port might be bad or something, but the PC and Mach are rock solid with BOB disconnected. Problem also occurs when the machine is hot or cold. So cooling isn't the issue. The hardest thing is that it is random, so if you make a change and the problem disappears, I think HEY I GOT IT!!!. Only to have it start acting up when I'm loading stock for a project.
Ah well.....keeps me off the streets.
Monty