Net connectivity problem

Making PCB Layouts, Manual routing, Auto-routing, Copper pouring, Updating from Schematic, Manufacturing Output
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skjoshi
Posts: 1
Joined: 04 Aug 2019, 02:23

Net connectivity problem

#1 Post by skjoshi » 04 Aug 2019, 05:53

I am novice to Diptrace,I designed a schematic in diptrace schematic, opened PCB Layout I opened schematic and Under route menu I selected layer setup as I want single side board I selectecd Top Layer as plane and bottom Layer as signal, Run "Arrange components"", Run Auto router ,Run Design rule under "Verification" no errors were found but while checking net connectivity errors several broken nets were reported.

To keep things simpler I disconnected connections between components in schematic except few components,again followed the above routine this time no net connectivity errors were reported
again I opened schematic and added some more components and converted to PCB, surprisingly this time net connectivity error included earlier OK Nets also.while no connections were made to earlier OK Nets

Please help me where I am wrong

Skjoshi

Alex
Technical Support
Posts: 3129
Joined: 14 Jun 2010, 06:43

Re: Net connectivity problem

#2 Post by Alex » 07 Aug 2019, 08:37

If check net connectivity reports that some nets are broken then they are really broken.
You can try one or few suggestions to improve result:
place critical components manually, other components using auto-placement feature
route critical nets manually, other nets using auto-router
if some unconnected nets remain you can route them manually, for example on top layer

doug12745
Posts: 17
Joined: 10 Sep 2018, 17:24

Re: Net connectivity problem

#3 Post by doug12745 » 30 Aug 2019, 12:38

Alex,
You state above that "reports that some nets are broken then they are really broken." Can you explain what "broken" really means? Can any additional information be found as to the reason "broken" is issued for a circuit or trace? I've examined most of these traces and they look good. However, most of my VCC and GNDs are reported "broken" but proper connections to the GND plane pour look good. I wonder if this problem has something to do with specifying the board layers settings and the copper pour planes? Is Diptrace PCB layout somehow confusing the presence of 4-layer boards with copper pours, and maybe a two-layer board? I am going to run this board through a Gerber check program to see if I can find any clues there. Thanks.

doug12745
Posts: 17
Joined: 10 Sep 2018, 17:24

Re: Net connectivity problem

#4 Post by doug12745 » 30 Aug 2019, 14:02

Alex,

Discovered the answer to the Net Connectivity Errors question.

If you are using copper pour inner planes for VCC and ground, these pours must be VISIBLE on the PCB layout page or a "broken" error will be reported. I would think that having the copper pour visible or hidden would be a visual editing feature allowing inspection of layout and traces. However, it appears that connectivity checking relies on WYSIWYG, and everything must be visible on the layout screen when Net Connectivity is run.

doug12745
Posts: 17
Joined: 10 Sep 2018, 17:24

Re: Net connectivity problem

#5 Post by doug12745 » 31 Aug 2019, 17:55

In my post of yesterday, I stated that "Net Connectivity Errors" were dependant of whether or not the copper planes were visible. That apparently is not true. The net connectivity errors I experienced mysteriously just went away. I have no idea why the errors were there in large numbers and then just disappeared. I don't recall doing much of anything. Evidently, when I made the copper pour plane visible it was just a coincidence that these errors went away. Strange behavior! Maybe it's sunspots!

Bacterius
Posts: 1
Joined: 03 Sep 2019, 00:14

Re: Net connectivity problem

#6 Post by Bacterius » 03 Sep 2019, 00:35

I had this problem recently and it turns out that it was because a via that was visibly inside a trace on the bottom layer was not connected to the trace's net. They would be electrically connected once manufactured but it seems Diptrace doesn't merge the nets in all cases. Not sure if it's a bug or if it's by design. I had not run DRC so it's possible it would have flagged it though.

I don't believe net connectivity cares about the currently displayed state of the board; it would be very confusing if it did!

Alex
Technical Support
Posts: 3129
Joined: 14 Jun 2010, 06:43

Re: Net connectivity problem

#7 Post by Alex » 03 Sep 2019, 09:18

Check net connectivity checks real connections regardless of visibility of layers or objects. If check net connectivity reports no short circuits and no missing connections you should trust it. But DRC and check net connectivity verify different things therefore you should run both of them.

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