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merging nets?

Hi,
This is related to my earlier query concerning covering unused pcb areas in copper (making a power plane). I have been successfully using that feature now (thanks), but I have one little niggling problem still. Heres a link to previous post...
 
 
I generally want to make as much of the board area grounded (to mop up interference/crosstalk between tracks).
Ultiboard generally has 2 nets connected to gnd (GND and Net 0). Dont understand why, to be honest.
I now usually make a power plane on copper top using net GND and copper bottom using net 0. This works fine most of the time, but with a couple of boards I'm working on at the moment, I can only squeeze in one power plane.
 
Rather than choosing between NET0 and NET GND, is there a simple way to merge/connect the two nets so that 1 power plane would include all the ground pins?
 
Like I said before- I dont know why ultiboard makes 2 seperate nets. I suspect this will need fixed with the forward annotate from multisim function, but I cannot figure out a way to do it?
 
Thanks in advance.
 
-Dalmation.
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I suspect the reason you see two grounds (GND and 0) is because you have both analog (GROUND) and digital (DGND) grounds in Multisim. By default, these are kept separate when you transfer to Ultiboard.

There are two ways you can connect the grounds. Which one you select depends on your particular design, but from your description, I think the first one is what you are looking for.

1. Within Multisim, select Options >> Sheet Properties. On the PCB tab, check the Check digital ground to analog ground option. You can now transfer or forward annotate to Ultiboard, and the two grounds will be connected.

2. Within Ultiboard, you can connect the different nets using a net bridge without causing DRC/Connectivity errors. Select Place >> Net Bridge, then choose and place a netbridge. If you have the ratsnest turned on, you can see that Ultiboard connects the nets through the netbridge.
Garret
Senior Software Developer
National Instruments
Circuit Design Community and Blog

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