fanuc background edit issues

  • Howdy Everyone,

    So i was trying to look at programs on one of our fanuc robots today in background edit trying to find were a DO was used. Everytime i select background edit, and scroll thru the program, it keeps throwing the robot into a hold, and doesnt' let the machine run. Is this some variable that needs to be changed? We have about 100 other fanuc robots and i have not seen it anywhere else.

  • AD
  • howdy,

    I checked that one, after i posted this, since i found that in another thread. It was set to True, like other robots, but thank you for the quick reply.

  • Bummer. I found that same thread, so made the suggestion.


    Do you have 2 robots of a similar model?

    A trick I use sometimes to find System Variables is using a comparison software (I use WinMerge) to compare ASCII backups of a Sysvars.sv (Sysvars.va is the ascii version). look for the differences, and maybe get lucky finding the Variable.

  • I had something like this happen on a job years ago. There was a double mapped bit on the DOs and the UOs. The DO wanted the bit low, but the UO wanted it high. The UO bit was "program running". UO almost always 'won'. However, going into background edit was enough to make the UO hickup for a few scans, and then DO would force the bit low, and then the PLC would promptly abort the program, since it thought the robot aborted.


    Its a long shot, but look for double mapped bits to the UOPs.

    Check out the Fanuc position converter I wrote here!

  • Thank you Nation,

    So i went and looked, are you talking about on the config page for the DO and UO, they both start at the same rack/ slot/ and start? is this what you are talking about?

  • Yep. Normally that is fine, as long as you don't use DO[1-20] for anything. If you try to set a DO, the UOs will set it back, and when you have two tasks fighting for control, and the PLC monitoring those bits, what I detailed in my previous post can happen.

    Check out the Fanuc position converter I wrote here!

  • So we figured it out. There was a DO turned on whenever a pop-up screen was shown, this was tied to a fault, which was tied to robot running program. So the pop up that said make sure you close out and save edits, would cause it to loose the hold UO

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