Eagle ver 6.3 - how to clear vias?

Discussion in 'Electronics Resources' started by atferrari, Jan 16, 2015.

  1. atferrari

    Thread Starter AAC Fanatic!

    Jan 6, 2004
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    Currently using Eagle ver 6.3, after almost 3 years.

    The most pervasive difficulty (at basic level): a via is assigned to change layer during a rerouting; trying to delete it later is not allowed because Eagle considers it as part of the net (do it in the schematics, it says...!)

    I recall deleting a via once after a sequence of wild attempts but could not repeat the series of events.

    Could anyone help me on this? Gracias.
     
  2. nerdegutta

    Moderator

    Dec 15, 2009
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    Have you tried to delete the wire in the schematic, and then re-wire it?
     
  3. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    There are two ways to clear vias that you don't want. The safest way is to use rip-up and destroy routing containing the via and the via disappears. While that is the safest way, it can lead to a lot of redundant work redoing all of one's beautiful artwork and polygons. So, here is what I do. I can almost hear the screams from others that will say you should never intentionally destroy F/B annotation.

    Here is the clue from HELP:
    First recognize that some vias are optional and others are mandatory to meet design rules. An optional via is one that you may add between layers that is not required by DRC. Once that via is named with a signal, you cannot simply delete it. For example, if you are knitting two ground layers together, there may be no or only one required via. The others are optional. An example of a mandatory via would be one on a signal that goes to the bottom layer to cross under other signals. Deleting that via would lead to a layer change and no way to get from one layer to the other, which would interrupt the signal and will result in a board-schematic inconsistency. Eagle sees that interruption as a deletion or change to the schematic, hence the warning.

    A simpler way for optional vias is to disable forward/back annotation by closing the Schematic. Then delete the optional via on the Board. Re-enable forward/back by clicking on the switch to schematic button and everything should be fine. Tested with 7.2.0 and 6.5.0 and had no problems with F/B consistency errors.

    Now, what happens if you delete by mistake a mandatory via? You will get the dreaded warning that board and schematic are not consistent. At that point, you have two choices. You can continue to click away with rip-up until consistency is repaired. Or, you can replace the via exactly where it was, and consistency will be repaired. Obviously, when you are in the no F/B mode, only mess with the vias. I guess there are three choices, you can always save a back-up copy before venturing into the wild, but I never remember to do that.

    John
     
    Last edited: Jan 16, 2015
  4. atferrari

    Thread Starter AAC Fanatic!

    Jan 6, 2004
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    Gracias ng and John for replying.

    I was doing rerouting in the wrong way, forcing vias when changing layer. Now, I relearnt how to change layers while rerouting (leaving vias to pop up when Eagle finds necessary !!) so ripping up is, at least for now, the solution to my problem.
     
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