Last winter I upgraded my cnc with a PMDX 414 and 407 board so I could run the mach 4 on my Chinese made cnc mill. The only issue I have is that it will give me the error message "PMDX: Could not disable the PMDX-SmartBOB-USB, error 'Cannot communicate with device'". It will do it randomly while running some times and other times just when I start the machine via the cycle run or select basically one of the commands on the screen to initiate a command to the cnc from a stopped or non-running state. For a while I assumed it may be a noise issue as it would occasionally occur when I started my pump for my coolant but it doesn't always. I have checked and swapped out USB cords and I never had this issue with the original OEM Chinese motion controller and mach 3.
The computer is a Dell Optiplex with windows 7 and I have to unplug the cord and restart mach 4 to clear the error.
Anyway I wanted to post this question to see if anyone else may have had or has this same issue and/or if anyone has a solution.
Thanks for reading.
Shawn

Hi,
I think you will get more help if you ask PMDX directlty. They have an excellent reputation for helping their customers.

You might also try an Email to Steve Stallings, a regular on the forum and one of the head honchos at PMDX.

Your description is the classic description for a glitch or electrical noise interfering and/or crashing USB communications.
USB can be very sensitive to such problems.

Craig