5 Replies Latest reply on Mar 11, 2013 4:55 PM by eperkin

    Maintaining design rules

    bruce.northrop

      Got one of those "Oh Crap" moments this morning.  Gerbers sent out, luckily only for quotes, but come to find out the design rules/clearances have changed from the original design.  The original revision had clearances of 0.012.  After I made schematic changes, ran the eco, etc, the clearances changed to 0.006.  How do I maintain the original setup?

       

      Thanks,

       

      Bruce N.

        • 1. Re: Maintaining design rules
          jduquette

          PADS added the feature to define the design rules in the schematic, so my guess is that you EDO'd a partially defined rule set from teh schematic to the PCB.  Here is how I would recover it.

           

          Open up the old PCB with the proper design rules and do an ASCII export.  Select only the design rules.

           

          Import those rules to the new PCB.

           

          (assuming the schematic and the new PCB match then) Back ECO from the PCB to the schematic so everything has the proper set of rules.

          • 2. Re: Maintaining design rules
            bruce.northrop

            I opened the two designs, the original and my new rev, side by side and edited the new rev to match the original.  So I got everything in the pcb fixed.

             

            Just trying to understand how this pcb could have been built and have basically a major disconnect between the schematic and the layout.  I guess when I get a new project, the first thing to do is review the design rules and make sure everything is correct.

             

            Thanks!

            • 3. Re: Maintaining design rules
              jduquette

              The design rules got added to Logic in version 9.something.  The last layout was probably completed with an earlier version of Layout when the rules where only in Layout.  So the first ECO with 9.# wrote over the proper rules with whatever was in Logic at the time.  I got burned on this once but luckily caught it like you before the fabrication.

               

              There is also a check box to not ECO the design rules back and forth.  That also makes it possible to have different rules defined in Logic and Layout.

              • 4. Re: Maintaining design rules
                bruce.northrop

                Thanks for the replies.  This should help me out.

                 

                Bruce.

                • 5. Re: Maintaining design rules
                  eperkin

                  If you have your rules set up into a class and change a connection on the schematic that net will be removed from the net class.This happens even when you don't include design rules in the eco from Logic to Layout.