KiCAD 6.0.0 PWR_FLAG: again issues

[tormyvancool]

But why?!
There is the flag PWR_FLAG (which is the most useless stuff ever, but it’s only in IMHO)
And it returns again and again an error. And connections are made correctly.

[gkeeth]

The error explains: you have two power output pins tied together.

This is usually a design error, i.e. if you have two regulator outputs shorted together you’re going to have a bad time (unless they’re designed to be parallelable…)

In this case it seems you have two PWR_FLAGs on the +12v net. Delete one and the error should go away.

Edited to add: if you don’t find the “input power pin not driven by any output power pin” error checking useful, you can disable it entirely in schematic setup → electrical rules → violation severity. But that won’t fix this particular error (except that you would be able to delete all PWR_FLAGs, which I guess would fix it )

[tormyvancool]

@gkeeth

The error explains: you have two power output pins tied together.

This is usually a design error, i.e. if you have two regulator outputs shorted together you’re going to have a bad time (unless they’re designed to be parallelable…)

In this case it seems you have two PWR_FLAGs on the +12v net. Delete one and the error should go away.

I have 2 power flags because without them, I get the same error. So I have to put this damn flag.
Why can’t we get rid of this “”“feature”"" once forever?

[gkeeth]

see my edit on how to disable the feature. If you attach the schematic or give a full screenshot, I can take a closer look.

You should not need two power flags on the same net – that won’t do anything beyond giving you the error you’re seeing

[tormyvancool]

@gkeeth

see my edit on how to disable the feature. If you attach the schematic or give a full screenshot, I can take a closer look.

You should not need two power flags on the same net – that won’t do anything beyond giving you the error you’re seeing

The only one places where i have this flag, are in the picture. There aren’t any other ones.
And in points where it returned the classical error about “when you haven’t Flags” …

EDIT: I have also to understand why this forum, automatically removes the quoted message and I have to re-edit and to re-add it.

[tormyvancool]

Now I have deleted one. It works BUT it doesn’t apply the same logic. I mean the -12V is with the Ground … ??

[gkeeth]

I can’t investigate further without the schematic, but the error says you have two power flags on +12v, #FLG0101 and #FLG0108.

I only see one on +12v from what you’ve shown, so I guess the possibilities are:

• there’s another one somewhere you haven’t shown
• +12v is shorted to -12v or another power net somewhere in your schematic
• there’s a bug

It works BUT it doesn’t apply the same logic. I mean the -12V is with the Ground … ??

I don’t follow, can you explain?

[tormyvancool]

@gkeeth

I can’t investigate further without the schematic, but the error says you have two power flags on +12v, #FLG0101 and #FLG0108.

I only see one on +12v from what you’ve shown, so I guess the possibilities are:

• there’s another one somewhere you haven’t shown
• +12v is shorted to -12v or another power net somewhere in your schematic
• there’s a bug

It works BUT it doesn’t apply the same logic. I mean the -12V is with the Ground … ??

I don’t follow, can you explain?

I repeat.

In the first image I posted, there are 3 flags located on:
+12V
-12V
GND (U4C PIN 7)

I deleted the one on +12V. Now it works. No errors. Why??

If I delete ALL 3 ones, KiCAD is asking to put the flag on the 3 I mentioned.

[gkeeth]

It’s hard to say without the schematic. Can you post the first screenshot again with the references shown for the three PWR_FLAGs? I want to figure out which one is #FLG0101 and which one is #FLG0108.

[tormyvancool]

please.

Flag 1:

Flag 2:

Flag 3:

For the moment I solved as I shown above, but it can’t be so each time again and again.
I will turn off the option you told me

[gkeeth]

Thanks for the screenshots. None of those are #FLG0108 referenced in the original screenshot, which might be because they were reannotated.

Can you run ERC again to see what the two conflicting flags are? Then do a Find (ctrl+F) for the references, which will highlight the two PWR_FLAGs that are conflicting. You’ll have to check “search hidden fields”

[paulvdh]

@tormyvancool

There is the flag PWR_FLAG (which is the most useless stuff ever, but …

The PWR_FLAG symbols are not useless, but you do have to understand how they work to make any use of them.

It pops up in 3 different FAQ articles:
https://forum.kicad.info/search?q=PWR_FLAG%20category:19

In short, normally the output pin of a voltage regulator is set to pin type “Power Output”, and ERC uses this to check if IC’s with a power input pin are connected to some power output.

If your PCB does not have a voltage regulator, then KiCad does not know where the power comes from, and for that you can use the PWR_FLAG symbols. I usually put them close to where power enters the PCB, such as a power connector.

Unfortunately, KiCad itself has no “spice like” behavior. Often nets are split because of fuses, filtering inductors or chokes or other parts, and this prevents the ERC from seeing the power connections, and there still is no real solution for this. The current workaround is to add a PWR_FLAG symbol again, after such schematic symbols.

[tormyvancool]

Sorry @gkeeth I rad you just now. At certain point I went ahead to finish the design and yes: meanwhile I re-annotated several times :-/

[gkeeth]

Fair enough, but if you have a chance to go back and try to recreate the error and do the Ctrl+F I suggested, I would appreciate it. If there’s a bug here it would be good to find it and get it fixed.