Connection difficulties in Schematics

Schematic
1

Hello, I am having difficulty making connections on my schematics. I struggle to get any lines (interconnections) to stick where I put them and I have a lot of black connection dots where there shouldn’t be any, or squares and circles at a connection point. The picture below shows the issue

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Here are my grid settings

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Any idea what settings I need to change to fix this? I think this may also have to do with my grid settings - not quite sure.

(I am on V7.09)
Thanks

2

The default grid size is 50 mil (0.050") or 1.27 millimeters.

This is the recommended grid for placing symbols and wires in a schematic, and for placing pins when designing a symbol in the Symbol Editor.

3

Yes the 0.002 inch grid size will be a problem for connecting wires in a schematic.

I sometimes use 0.1 inch grid for symbols. This is OK because it is an even multiple of 0.05 inches. Of course the idea of “inches” in a schematic is a bit arbitrary. I do not know that there is any real world scaling. The main thing is that the KiCad community has agreed on the 0.05 inch standard.

Do not use pi^e mils as a grid size in schematic editor. :smiley:

4

Are odd multiples not allowed? :crazy_face:

5

Sounds like an odd question. :slight_smile:

Do you want to discuss it over some cherry pi?

6

I’ve set everything to the 50mil grid. I actually think the biggest problem is getting the wire to attach. I would expect if I try to make a connection to a circle of square, the wire tool would snap to the connection - how do I fix that? It really fiddly and many times there’s no connection so I have to check it with ‘Move’ - if I move the component, the connection is actually not made, so I go back to it and try to redo it.

image

Thanks

7

Try this: Select everything in the schematic with Ctrl-A, then right mouse button > Align Items to Grid. This may cause some items to be aligned but disconnected from wires.

Otherwise start all over with the correct 50 mil grid.

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8

The best solution. There have been so many requests since V4 days to make it really hard for users to change the defaults. Holding down the CTRL key while moving text allows free movement without changing the grid.

9

This is all assuming the spacing on the symbol pins is also correct. Is the symbol from the default KiCad library, or did you make it yourself?

1 Like
10

Just because someone at some point will come along and be confused by your humorous comment, the correct answer should be:

The grid must be an integer multiple or submultiple of 0.05 inches to use the KiCad library symbols.

I’ve worked successfully with a grid of 0.025 inches when I created a few custom symbols that needed to be smaller than the normal KiCad library standard.

The OP’s grid of 0.002 inches is an integer submultiple of 0.05 inches, so it would work. However, it would make it unnecessarily challenging to get the wires to connect to the pins. KiCad requires that wire endpoints and pins match exactly to connect (the units for the schematic are either micrometer or nanometer, I can’t remember which). Too fine a grid will result in something that looks like it connects but doesn’t. There’s no benefit in having such a fine grid.

11

Make it positive integer :wink:

12

As a one-time mathematics major in college, I could say that it’s a real positive integer (no complex numbers) multiple. But we’re too far off-topic to be helpful.

13

This may not help in your situation, but v7 is quite old and v8/near-future9 have this:

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image933×381 17.5 KB

This was added at least partly to lessen the problems with bad grid for “connected items”/wires – you can set finer grid for non-critical text positions and graphics so you don’t need to explicitly change the grid, maybe ever.

But what you can do in v7 is to use Align Elements to Grid. This, along with re-doing the whole schematic, was already mentioned above.

1 Like
14

Its a default KiCAD symbol

15

Looks like I need to upgrade to 9!

16

9 isn’t out yet, release candidate yes but not the formal release. If you are going to try it treat it as you would nightlies . . . caution and don’t rely on it, use a BACKUP of your project.

1 Like
17

The point is:

  1. The symbols pins need to be on a 50 mil grid (either assure this as I do when editing symbols, or use KiCad symbols). Using a multiple of 50 mils (such as 100 mils) satisfies this requirement.
  2. The symbol needs to be placed in the schematic on a 50 mil grid. Doing this on a multiple of 50 mils (such as 100 mils) satisfies this requirement.
  3. Wiring the schematic on a 50 mil grid. To keep it simple, use only a 50 mil grid. No bigger and no smaller. Smaller grid (or CTRL key to suspend the grid) is useful for moving text but will add difficulty for wiring.

I promise you: When I have adhered to the above, wiring the schematic has always been very easy.

2 Likes
18

Won’t solve your problem. Get your grid right, then it’s a walk in the park.

3 Likes
19

Looks like my problem is completely solved. I selected everything and then 50mil grid. Working perfectly now. Thanks to all for pointing me in the right direction. AndrewR

4 Likes