My new special Footprint and errors in ERC & footprint filters

[grayb]

My new special Footprint and errors in ERC & footprint filters

In my circuit, I have some PCB-mounted fuses. However, due to space, I am looking at using resettable fuses.

As I do not know the exact fuse rating yet, until it is built. It is easier with actual fuses to size up or down on current ratings to suit.

But in using resettable, they vary in size and pin leadout positions.

So to cover every eventuality, I decided to make the footprint to accommodate different resettables.

This is when I start getting ERC errors.

I would like advice and guidance on what I might be doing wrong.?

As I think there might be 2 errors in what I am doing.

I change things, and I get more errors

I just cannot get rid of the footprint filters ‘polyfuse and PTC’ or is there way of incorporating them into the symbol ?

The footprint below has two pads named ‘2’ to accommodate the different pin centres. I am led to believe that Kicad software recognises this and joins the 2 pads together with copper track. Is the copper track the same width as the pads. But the above symbol only shows 2 connections. Do I need to do anything with the symbol?

[eelik]

I wonder why you are asking about the same subject again. I have an error message about footprint filters

[grayb]

In this instance its because the filters do not go away. The filters keep coming back.

I can switch the 3 filter buttons off, but no effect.

I can delete the symbol and remake it, and they are still there.

I have deleted keywords, no effect.

Something not right, I cannot put my finger on it. Its as thou there is a memory cache problem.

But I am no expert. I have spent 2 days trying to sort this problem out, and you run out of ideas.

So I have gone onto another part of my project.

[eelik]

@grayb

In this instance its because the filters do not go away. The filters keep coming back.

But based on the information you have given us, the answer is the same.

@eelik

But whether you want to do exactly that or something else, depends on your use case, for example if you want to reuse the symbol/footprint combination, whether you are using a standard KiCad symbol or a symbol in a personal or company library, etc.

The basic options to get rid of that message are:

• Suppress the message – you don’t need it and you don’t have to change the filters. No harm done. In general, there are only few use cases where this message could be important.
• Change the filters in the individual symbols in the schematic. I already gave instructions for that.
• Change the filters in the library symbol which is in a personal writable library and then update the symbols in the schematic from the library.
• Maybe something else, but doesn’t come into my mind.

You have to have some basic understanding about the library system in KiCad. Look into the FAQ section of the forum. You have to know what workflow you want to use. Otherwise you can only find another ad hoc solution until another problem occurs, etc.

[eelik]

I looked through you images again. It’s possible that this is what you have tried to do:

@eelik

Change the filters in the library symbol which is in a personal writable library and then update the symbols in the schematic from the library

but you haven’t done the last step, updating the symbols which are already in the schematic. KiCad doesn’t update them automatically when you edit a library symbol. Use Tools → Update Symbols from Library.

[grayb]

There is something astray somewhere.

I have saved and closed down Kicad for a number of hours, then reopened Kicad.

Suprise suprise all the ERC errors have cleared. I honestly did not do anything.

No Filter problems nothing.

I know the problem still could be me, but !!!

Thanks to everybody who have kept with me.

[jmk]

@grayb

The footprint below has two pads named ‘2’ to accommodate the different pin centres. I am led to believe that Kicad software recognises this and joins the 2 pads together with copper track. Is the copper track the same width as the pads. But the above symbol only shows 2 connections. Do I need to do anything with the symbol?

Kicad recognizes the two pads numbered “2” may be joined. Kicad does not join them. Kicad only places a ratline between the two pads and will complain bitterly in the DRC if you do not place a wire between the two number 2 pads.

Nothing needs to be done with the symbol.

[eelik]

And before restart you refreshed the ERC messages by running ERC again (clicked the Run ERC button in the dialog)? It’s of course possible there’s a bug in KiCad.

[grayb]

@jmk

Kicad recognizes the two pads numbered “2” may be joined. Kicad does not join them. Kicad only places a ratline between the two pads and will complain bitterly in the DRC if you do not place a wire between the two number 2 pads.

You are absolutely right. You can just see the ratline between the two 2’s.

[jmk]

If I’d been wrong, I’d have had to bear the humiliation of many other members telling me so.

If you have trouble seeing ratlines, don’t forget, they are adjustable.
You can even have your PCB looking like a circus tent if you wish.

Preferences > PCB Editor > Editing Options and the Appearance Manager get you there.
The different colors for ratlines are the result of using Net Classes

I find that changing the ratlines to very thick bright green, when a board is nearing completion, is a good way to easily notice what tracks I have missed before running DRC. It is generally easier than playing “spot the red arrow”.

[retiredfeline]

In fact the ratsnest lines could also appear between the pad 2’s and the nearest copper in that net. There is nothing special about this behaviour. All pad 2’s are in the same net because the schematic connects pin 2 with other pins in the net. Thus the PCB editor will require you to connect up all pad 2’s with copper.

I use this behavour to make a “superLED” footprint for a display segment made of 4 LEDs. In the footprint I have assigned the pad numbers for the superLED footprint thus:

1-3 3-4 4-5 5-2
D1  D2  D3  D4

As far as the schematic is concerned, it’s a single diode with pins 1 and 2.