"Un-Routed Net constraint" error makes no sense! - Page 1
Forum section: electronics / general

author: hansibull
author_rank: Regular Contributor
timestamp: June 03, 2017, 04:27:18 pm
content: Hi!I've been working with Altium for a while now, and It's just amazing (especially after working with Eagle)! However I've stumbled across an error I can't solveI'm working on a four layer PCB. the top and bottom layer is ground planes, and "layer 2" is 24V. This leaves layer 3 for the signal layer. The following screenshot is the output stage of a class D amplifier. On the top layer there's a poly cap together with an inductor. To make sure the polycap has a proper ground connection, I've added three vias close to the ground pad. (Note the "light" purple polygon on the pics are the internal 24V plane)As you can see theres a little white circle and two lines on one of the vias. After running the DRC I get the following error:QuoteWhy do I get this? The via is just connecting the top and the bottom layer, and has nothing to do with the cap C603. What's even stranger is that if I move the via away, I get an error from one of the other vias. See pic below.What's causing this, and how can I fix this? I'm running Altium Designer 17.0.11.

author: Fgrir
author_rank: Regular Contributor
timestamp: June 03, 2017, 04:58:03 pm
content: I think the error is that C603 pad 2 is not connected to GND. The via just happens to be the nearest GND that Altium can find, so when you move one away it just picks another to use for your error.

author: hansibull
author_rank: Regular Contributor
timestamp: June 03, 2017, 05:05:40 pm
content: I'm pretty sure the pad is connected to ground. It is in the schematics atleast. Here's a screenshot of the of the top layer:EDIT:I tried to move the three vias 0.2mm to the right, and now the error is gone. Does this means there may be some kind of rule that prevents the via to connevt to its polygons if placed too close to a pad?

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 03, 2017, 05:32:53 pm
content: you must activate polygon pour in order DRC to see the connection...

author: hansibull
author_rank: Regular Contributor
timestamp: June 03, 2017, 05:40:02 pm
content: QuoteActivate? None of the polygons are shelved, and there's no "Activate" or "Enable" button in the polygon manager. What's weird is that there's lots of other components on the board that got the vias much closer, but they doesn't case an error.

author: Mechatrommer
author_rank: Super Contributor
timestamp: June 03, 2017, 08:51:59 pm
content: Quote from: hansibull on June 03, 2017, 05:40:02 pmyes, not shelved but... i dont see top layer polygon pour in the 1st picture. where did it go?

author: D3f1ant
author_rank: Frequent Contributor
timestamp: June 05, 2017, 07:46:02 pm
content: Suspect you got an big island there. Is there any tracks on the bottom layer cutting it off?Is the bottom layer poured and not shelved?

author: sean0118
author_rank: Frequent Contributor
timestamp: September 05, 2019, 07:29:01 am
content: I know this is an old thread, but I just had the same problem. I'm pretty sure it's a bug.I placed a second GND polygon on the top layer to join the pad to the vias. I then set it earlier in the polygon pour order, so it pours first, then the larger GND polygon over the whole board pours last.This fixed it for some reason...