No connection between circuit elements

Hello to All,

I have a new fan and still a beginner user of the KiCAD and so sometimes I face seemingly unsolvable difficulties.
Recently I experienced errors noticed by the in-built checker such as ‘pin connected to other pins, but not driven by any pin’ and ‘pin not connected’ but suppress the latter with “no connection flag” would be futile I think.
I do not really understand why the Editor does so, because I meticulously attached wires with PWR & GND parts. In addition, it referred to such problems at many other areas but after some redrawing those ones simply disappeared from the problem list, reduced from 8 or 7 to 3 or 2 overall.
I wasted so much time with these errors and I could move forward with the finalisation process.

Please help me with it because by this time I lost the faith in finding a solution and there is no one to help with it around this time.
I have print-screen on this issue, so I can show it up if it would be helpful.
Thanks for the help in advance.

That should mean that you connected in one net several "Input’ pins with no “Output” pin driving that net. I don’t use ERC so I’m not sure of what I am saying.

Can I suggest that you have a look at the FAQ section. The ‘Pin not driven error’ is a very common issue and there is comprehensive advice about how to deal with it here;

The ERC is there to help you - not to fight against you. If you follow good design habits you should find that the errors will help you ensure that your design is what you are expecting. It is often helpful to add ‘No Connects’ to ensure that the design intent is explicit.If the layout is wrong you may end up with a board that doesn’t work - you can’t expect the layout process to interpret what you thought you designed rather than what you actually drew.

It would be helpful if you shared your design (I see you offer a screen shot) but you will find that the forum software expects you to spend a little time looking around and exploring the forum first so you may find that you cannot post at present (I’m not an admin so can’t check). I would suggest that a good look around the FAQ section would be a very good place to start. After you have reached the basic level of trust and, if the looking around hasn’t answered your questions you will then be able to upload your project or a screen shot.

1 Like

Hi Piotr,

Thanks for your interpretation.
I saw a tutorial video on this matter but it was not entirely clear how sometimes my approach managed to fix it and sometimes not. Ok, I will try this one. So, we will see soon and get back with reflection.

Dear John,

Yes, you are right. Thanks for the suggestion.
First, I searched and looked for a specific similar topic at the forum but I did not find a good match. After all, it could and can be my mistake or incompleteness of course. It would be pretty natural.
Ok, I will go over this once again then see and experience what happens.
Best wishes,

Just to notice one more detail on it.

I am really not a EE and PCB designer, only trying to draw my calculated and suggested sensor design. I had some knowledge with lab-on-chips design but certainly not with PCBs.
So, in my case, I am bit puzzled because in my design there are no chips, other circuit components, only electrodes, tracks and vias (drawn as wires and/or buses). So, I used multiple “no connection” type flags for the electrode ends.

You might like to post your design on the forum as it is not entirely clear from your description what you are trying to achieve. For instance a ‘via’ is a feature on a PCB to swap the trace between two layers. Your schematic is simply a logical representation of the network of connections you need. You don’t need to specify the vias in the schematic. You can attach a screen shot or zip up the whole project and attach that. It might be easier to see what the problem is.

All right. I myself think it is the easiest and fastest way towards a viable solution.
I attached 2 screenshots of the 2 different type design schematics. Both of them contain two connection errors which are hauntingly similar I had previously with additional 6 or 7 cases but some way it was managed to restrain it to 2 overall.
I am very curious about the possible solution.
During the meantime, I am going read other sections to which I am a newbie:)

And so here is this the second one (just because I could not upload 2 at the same time).
Is it similar to the first one or different in nature of the connection problem?
How do you see it John?
Thanks for your help!

There are a number of issues here. We can’t see the whole layout and, although KiCad tried to locate the error, the actual problem may be elsewhere.

Firstly, you have a bus which has a ‘no connect’ - i can’t think of a good reason for this - you have also used busses elsewhere and suspect that they are not connected in the way you think.

In your second picture you have a load of no connects (NC) that are not actually on a wire and a load of junctions on a wire where they are unescessary.

Have you adjusted the grid from the result 50 setting? Some of your NC symbols look off the grid. Are any of the symbols your own of are they all from the KiCad library?

There are some other general style points - crossing wires, no wires between GND and the connector (not essential but helps with net highlighting) etc.

TBH i think we need to see the whole layout to see what you are trying to achieve here. Zipping up and attaching the project is probably the best option.

In picture 1:

  • you not connected pin SH to anything so why you are surprised by error information,
  • with GND it would be good to see other places where GND was used.

In picture 2:

  • only one PWR_FLAG for GND would be enough, the second is not needed (this is only my observation with no connection with any error info).

Dear John,
I attached a new version of the 2nd one with input PWR lines (as described in other forum section) and also with partial use of wires between the PWR & GND lines. So, as it clearly seems exchange of the PWR-FLAG to any other PWR (AC or DC) input did not help. Actually it could not have been problem what so ever. The wire connection between VAC & GND is still busted at the GND part. Should the latter change to other, input GND type? I will try soon.
All these symbols stems from the genuine KiCAD library (no imports from other sources).
The grid setting is the finest, 1 mil or 0.0254 mm. This is to help my work whilst drawing. On the other hand, some sections are certainly off the grid. Is it of huge relevance? I think it should not be by any circumstance.
What do you think the real reason could be for the KiCAD to complain via the ERC?

Eeschema determines if parts are connected by the exact location of the pin end. All KiCad parts have the pins on a 50mi (1.27mm)l ‘grid’ (the units are irrelevant). If you set the grid to a different value, the pin ends may not lie on the same grid as other components and you may have difficulty connecting them up.

Really, don’t touch the grid in eeschema unless you absolutely need it for exactly positioning some text or something and then remember to switch it back immediately. You can see points where pins are not connected by the presence of a small box at the pin end - I can’t see any points on the screenshot but there could be elsewhere. If you have used different grids at different times you may have issues connecting this up.

I really don’t know what you are trying to achieve with all the connection dots and the NC symbols between them - this is meaningless in the schematic. Neither the connection or the no-connection have any meaning here - the connection is implied by the wire and the no connect is not on a conductor (and only works on the end of a conductor anyway). Remember, the schematic is an abstraction of the layout and not a visualisation of the PCB.

Yes, I think I just managed to experience this sort of issue, connect-ability of the conductor lines.
I did not know it is so strict to go with default grid setting in the KiCAD. OK, I will try to stick with fine grid on this occasion but in the future I will stick with maintaining the original grid setting.

Connection dots and NC symbols are on short conductor lines, so short conductors cannot be seen at all. It might have been clearly better to draw the conductor lines longer. So, yes their meaning is the abstract layout of the PCB (sensor) wiring.

Overall, I still feel myself far from the solution. Ahh, it is so hard to proceed fast even though I went over other forum sections.

Dear John,
Could we have a personal correspondence?
I would send you description of the sensor designs accompanied with the proper schematic and footprint edited files.
Would you be so kind as to help me how to draw prototypes in a proper way?
Please let me know your thoughts.
Kind regards,

The way you connect to the SH pin kind of indicates that you don’t really understand the buses in kicad. Right now no connection will be made to the shield of that connector!

Right now buses are limited to represent a parallel communication bus like for example the address lines of a RAM chip where that has connections of the style addr0, addr1, …, addrN. (Future versions will have more powerful options)

More details:
The blue line (the bus) really is just a graphical line. It itself does not make any connections.
Connections for buses in kicad are really only made by use of labels (global, local or hierarchical). And there is a special bus label that allows collecting multiple labels at once. This is by use of the special syntax <common prefix>[<idx low>…<idx high>] and every bus entry label then is <common prefix><idx> with <idx low> ≤ <idx> ≤ <idx high>. typically the “bus label” is then placed “connected” to the blue line (the bus) and the entry label somewhere on the green one (the wire).

You may want to consider a drafting or drawing program rather than Kicad. Maybe a spreadsheet would be helpful.

There are many features of Kicad which will be obstacles rather than beneficial tools. What you have drawn so far breaks general rules that will be difficult to explain.

Perhaps you could attach a pencil drawing to assist. It seems you are only interested in a drawing rather than a pcb.

If one is really only interested in a drawing then there is no reason at all to run ERC.

Thanks Rene for the clarification, it is helpful for understanding. Sometime earlier I corrected this matter, so by this time I am over this issue.

I was not really focused on drawing rather than not knowing exactly what and how to do in my case. Nonetheless, thanks to John Pateman, now I know what & how.
Thanks iabarry for the nice and welcoming comment:)