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n/a
41 Posts |
 Posted - 02 Dec 2011 : 15:37:15
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When I try to back annotate from PCB to schematics, the system not only reports it can't find some components but also that it can't find some nets either.
The components definitely do exist, but the nets do not and don't even show up in any of the net reports for any of the schematics or the PCB!
Any ideas please? |
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Iain Wilkie
United Kingdom
1015 Posts |
Posted - 02 Dec 2011 : 16:22:43
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Back annotation is for component designations only, you cannot add components or nets in the pcb editor and annotate them back to the schematic.
Iain |
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n/a
41 Posts |
Posted - 05 Dec 2011 : 10:24:45
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Thank you Iain, I'm aware of that.
I should say I tried the back annotation before I'd done any renumbering of components on the layout, simply to see what would happen. Instead of doing what I'd expected and hoped for, i.e. reporting no changes to transfer (or similar), it spat out a long list of components it claimed it couldn't find on the schematics, despite them being there and not having changed since being translated to the PCB in the first place. It seems the problem was somehow related to the problem of the spurious net (sorry, I said nets before) which didn't exist anywhere but which the back annotation function was sure existed on the PCB but not on the schematic!
I got round the problem by creating the offending net on the schematic (by linking a couple of spare pins on a connector together) and forcing the new net to have the same name as the non-existant one. I then went to the PCB layout and repeated the back annotation and it then performed correctly. I then removed the schematic connection and forwarded that as a design change to get rid of it, and then felt safe to do what I'd intended in the first place, which was simply to renumber the PCB components and then bring the schematics into line.
This must have been a glitch or software bug somewhere, but you can bet I won't be able to recreate it again! |
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edrees
United Kingdom
779 Posts |
Posted - 05 Dec 2011 : 10:52:26
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Settings=>Design Tech=>Nets
Then click on "Delete Unused". This ensures that all nets without connectivity data are removed from the design and are not forwarded to the pcb layout etc. |
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n/a
41 Posts |
Posted - 05 Dec 2011 : 13:30:41
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| Thanks edrees, but the offending net didn't show up in that section for any of the schematic sheets or the PCB, hence my problem - why did some element of the software think it was there at all?! |
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Back annotation headaches