2020 drive with cnc4pc breakout board

[najnielkp]

i have a strange problem with the 2020 drives . when i use the tuning software i can get the motors to run well. the parallel cable is connected straight to the computer. when i use the cnc4pc optoisolated breakout board between the pc and the 2020, the motors run very rough and erratic when trying out in mach3. connecting the parallel cable straight from the computer and 2020s in mach3 , they run silky smooth. does the optoisolation not work with the rutex products?
i assumed that the breakout board would provide a "cleaner " signal for the drives.

[Konstantin]

This symptom could be a failing ground between the PC and the drive.
It happened to me a lot when I test drives with just a couple of lead STEP and DIR and if I forget to share the GND the behavior is erratic.

Konstantin.

[najnielkp]

thanks for your reply. would not this defeat the isolation?

[rutexus]

Gentlemen,

Most of the time the break out boards add complexities to the set up. I try to discourage people from using them. The Rutex system was designed to be simple, and it works best when hooked right to the pc mother board or parallel port.

Tom Eldredge
Rutex LLC

[Konstantin]

Well you heard the man.
I was thinking it too. If the inputs/outputs are all optoisolated then the ground is isolated too. I guess using a wire to join grounds is the way to go to eliminate the erratic behavior. But will it defeat the purpose of having an optoisolation?


Konstantin.