3 Replies Latest reply on Aug 8, 2014 6:10 AM by volain

    forward annotation problem.  BIG problem.


      This one is a little difficult to describe, but here goes.  I've got a board that's completely layed out.  Now, I went and made some changes to the schematic (added and deleted some parts, changed some connections), but when I forward annotate, the process changes the wrong parts. 


      More details: I've got two components of the same type, U5, and U11.  I added a third component of the same type, U77.  U5 and U11 should stay put, and U77 should be imported when the ECO is processed. BUT, what happens is U5 get changed to U77, but stays in the same physical location, and the old U5 now gets "imported" to the lower left corner.


      I tried several methods with the same results-running PCB Interface from DxDesigner, running compare/ECO from PADS, doing Forward Annotate from the DxDesigner link in pads.  When I run the Compare/ECO, I see in the part differences section of the report




      U5                          U77


      This is bad.  What's going on?

        • 1. Re: forward annotation problem.  BIG problem.

          When running the Compare/ECO in PADS Layout try clicking on the Comparison tab and set the Name Comparison Options radio button to the 2nd selection where it says "Compare Net Names and Reference Designators. Prefer to Add ot Delete Parts instead of Renaming" and see if you get better results in the ECO file.



          • 2. Re: forward annotation problem.  BIG problem.
            David Ricketts

            If alternate Name Comparison Options don't work, you may have to "seed" the changes. ECO does have problems with identical parts with parallel connections, decoupling caps being the biggest example, but as you've found, if the identical parts have enough of the same nets, you may not get the results you want. By "seeding", I'm talking about a partial manual ECO change to change the results of the ECO process in your favor. In this case, just copying U5 and labeling the new part U77, then running ECO Compare, may be all you need to get the results you want.


            As a general note, never trust ECO forward and backward to be an automatic process. Always review the changes first, for if nothing else, it's just to make sure the changes are what you expect them to be.

            • 3. Re: forward annotation problem.  BIG problem. <Solved>

              Thanks, that did it, Mentor BIll.