ERC errors in hierarchical sheets

[VDG]

Hello,

I’m a newbie with Kicad
A have a “root” sheet with two subsheets.

When I highlight a net in a subsheet, the net is highlighted in the subsheet and in the root sheet. The connection name (coming from the root sheet) seems to be correct.

When I run ERC, it gives me errors about hierarchical labels in the subsheet “not connected”, and I can’t get rid of these errors.

I’m using Kicad 7.0.8

Can anyone help me ?

Thank you

[bidrohini]

Here are some threads about the ERC error. You may find some clues from these.

Problem with ERC in hierarchical sheets (pin not driven)

Hmm, I’m wondering about a few things in your design. Why not take the LM317 voltage feedback after the BC547 so that it takes into account the BE junction drop? And the BC547 isn’t a high power transistor and the LM317 can supply a higher current so why the emitter follower in the first place? And the input side, why the two series reverse diodes and the two series capacitors? Were you trying to do a voltage doubler from AC input?

[6.0-rc1] Missing ERC error for signals on hierarchical sheets

Hi, in my design, I have some signals, which are connected to a hierarchical block. But then the ERC is not marking this signals, when they have no other connection in the design. You can see, that signal ECU.EAL_SW_MON is only on one sheet (9) and nowhere else, but it isn’t marked (same issue with signals connected to a bus). [image] In the same design, on another place without the hierarchical sheet, the error is marked (couldn’t attach the image with the marker, because new user). Is th…

[mf_ibfeew]

You will get the best help if you attach your project (Kicad main manager–>File–>archive project) in your post.
As a new user you have to get the next user-level first (as anti-spam countermeasure). Read and followthis link: New Member Information.
If you have promoted yourself to basic user level you could attach your project.

two guesses:

• hierarchical labels are offgrid and therefore not connected to the wires
• no other symbols connected to these wires (it’s not enough to have a wire connected to the label, there must be a real symbol on the other end of the wire)

[VDG]

io-card-2.zip (610.6 KB)

Hello
Thank you for your reply
As a newbie, I’m not sure to understand exactly what you wrote.
My project has been attached to this reply

Thank you for your help

[Claudio.Lorini]

i think that if you connect a net label to the hierarchical labels it should work.
something like:

[paulvdh]

This screenshot should make it obvious:

Edit: I made an error here. Read a part of the manual as a result, and it states:

Labels that have the same name will connect, regardless of the label type, if they are in the same sheet.

You could add local labels and connect them to the hierarchical labels as Claudio Lorini suggests, but to me it’s more logical to delete the local labels and use the hierarchical labels on the locations where the local labels are now.

If there is still some confusion, then read the chapter of the KiCad manual about the different label types and their use.

[VDG]

Thank you for your reply.
But there is still something that I don’t understand:
When click on the 3V3 label just on top of the STP16CPC26 on the leds sheet, the status bar shows a connection name /VCC3V3 (part of the root sheet). If I highlight the net, it shows connections in the leds sheet and in the root sheet. Isn’t this a sort of discrepancy between what express the schematic, and what express the ERC ?

[mf_ibfeew]

thanks for the project, now you can get better answers.
The connection in your schematic is really ok (as you already have checked with the “highlight”-command). But the “label not connected to something”- ERC check does two things:

• check if the label is graphically connected to something (this is not the case in your project). This prevents floating (forgotten) labels. This requirement is not fulfilled in your case → therefore the error. Just adding a small green wire (like claudio said) is enough, the local label is not needed.
• as a second step: is this connection going somewhere to some other symbol/net (this prevents to have just one single graphic net + label floating around) (this requirement is fulfilled with your schematic - as you have tested with the “highlight connection” command)

One correction:

Different label types do not automatically connect to each other just because their name is the same.

this is false, as your project shows all labels with the same name connected very well together.

[VDG]

Thank you for your help, and the help of Claudio.Lorini.
Your answers drive me to understand thinks, and to help me correct those errors

Best regards
Vincent