Nets have merged by accident and I can't separate them

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marbol
Posts: 13
Joined: 23 Sep 2016, 15:31

Nets have merged by accident and I can't separate them

#1 Post by marbol » 15 Feb 2017, 17:38

I have a fairly detailed schematic with around 1100 pins.

I have two nets, +12VP and GND which are separate nets in the schematic.

However, I somehow got them merged together so that if I hover over any pad that is supposed to be GND it shows as +12VP. I look at all of my ground pours and they are all now connected to +12VP and not GND however they were GND when I started.

When I try to renew from schematic it says that there are differences and lets me choose whether to use the schematic or the layout. I choose schematic and still the nets remain merged in the layout only.

I've searched to see if this has happened to anyone else before and I see a post from 2010 where support asked the person to send them the two files.

What should I try doing first to get these unmerged? I've tried looking to see if somehow the nets got shorted in the layout but I don't see it except for the copper pours. Do I need to rip them up? I've tried to change them back to GND but GND does not show up in the drop down list any more.

Tomg
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Posts: 2028
Joined: 20 Jun 2015, 07:39

Re: Nets have merged by accident and I can't separate them

#2 Post by Tomg » 16 Feb 2017, 00:19

It sounds like you accidentally merged one Net with another in the Schematic Editor. There is a flaw (in my opinion) in the DipTrace Schematic Editor that allows this to happen without displaying a warning that the Nets are about to be merged. If you can find the accidental bridge connection in the schematic, right-click on the wire and select Delete Wire in the pop-up menu. Rename the two separated Nets as desired. I've included a video named "merged nets" (below) that shows a simple example of the DipTrace flaw with a solution. After the schematic has been corrected, open the PCB layout, disconnect the offending copper pour from its Net (for Connect to Net:, choose None), use the Renew Layout from Schematic tool and then connect the copper pour to the desired Net.
Attachments
merged nets.zip
(1.71 MiB) Downloaded 142 times
Tom

marbol
Posts: 13
Joined: 23 Sep 2016, 15:31

Re: Nets have merged by accident and I can't separate them

#3 Post by marbol » 16 Feb 2017, 05:46

But everything in the schematic is correct. The nets are only merged in the pc board layout. When I update from schematic the GND net shows up because it asks me if I want to use the schematic or the layout, and I choose schematic. But the nets remain merged in the layout only.

Tomg
Expert
Posts: 2028
Joined: 20 Jun 2015, 07:39

Re: Nets have merged by accident and I can't separate them

#4 Post by Tomg » 16 Feb 2017, 05:48

Try disconnecting all copper pours from their Nets, then connect each one to the desired Net (one at a time) to see what happens.
Tom

marbol
Posts: 13
Joined: 23 Sep 2016, 15:31

Re: Nets have merged by accident and I can't separate them

#5 Post by marbol » 16 Feb 2017, 06:17

I'm going to have to remove the copper pours. I tried to change the net of each pour back to GND however the GND net isn't there any more.
Also I couldn't choose to have them connected to no net at all. I tried removing the net and having it connect to nothing and that wouldn't work either.

I really don't want to have to remove them completely, but I think I might have to.

I've also tried removing all static vias that went to the GND layer. That didn't work.

Is there a way to tell each copper pour that I don't want to attach it to any net?
Or can I create a dummy net and attach it to that?

Tomg
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Posts: 2028
Joined: 20 Jun 2015, 07:39

Re: Nets have merged by accident and I can't separate them

#6 Post by Tomg » 16 Feb 2017, 07:35

marbol wrote:"...Is there a way to tell each copper pour that I don't want to attach it to any net?..."
1) Right-click on the copper pour outline and select Properties... in the pop-up menu.
2) In the Copper Pour Properties dialog window click on the [Connectivity] tab.
3) Click on the down-arrow in the Connect to Net: drop-down list and select None.
4) Select OK.
Attachments
connectivity.gif
connectivity.gif (52.33 KiB) Viewed 923 times
Tom

marbol
Posts: 13
Joined: 23 Sep 2016, 15:31

Re: Nets have merged by accident and I can't separate them

#7 Post by marbol » 16 Feb 2017, 17:58

That didn't work. But I found the issue. And I feel really bad and stupid.

It was my fault since I had a component that had crossed net in the component itself.

I guess I'd better learn to be more careful.

jet31
Posts: 7
Joined: 01 Mar 2017, 23:53

Re: Nets have merged by accident and I can't separate them

#8 Post by jet31 » 03 Mar 2017, 15:44

In my first encounter of DipTrace this also happen to me , where my gnd and my Vcc ara accidentally connected.
It was a big miss coz there a lot of component connected to the two signal.
This is something that DipTrace should also correct.
But I found a way in order this thing not to happen again in my schematic.
My Trick is that:
I used different color in my gnd signal and different color on my Vcc.
As I connect a new component to my gnd if will automatically change its wire color to my gnd color
So in this way I will not mistake my wiring anymore. just use color coding.

JET,
Attachments
color-coding-schematic.png
color-coding-schematic.png (36.12 KiB) Viewed 898 times

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