Again, to make it as simple as possible (simplifying a bit):
This required a second reading, but if I understood you correctly, you understood correctly.
A ânetâ is an abstract entity, and the netlist itself is generated in the schematic, and it does not have necesarrily to do with physical copper in PCBnew.
From the example screenshot eelik posted:
Net 1: R1 pad 1 and R2 pad2 are connected.
Net 2: R2 pad1, R3 pad 1 and R4 pad 2 are connected.
This netlist is already made in the schematic by drawing the wires between the schematic components. For most components the pin numbers are visible, but resistors are one of the few components for which pin numbers do not add mostly clutter in the schematic, and they are therefore hidden (but they still exist).
The netlist can be made visible by printing it to a file. In KiCad V5 this can be done with: Eeschema / Tools / Generate Netlist FileâŚ.
OK, thanks understood. Your schematic explained it better than my words.
Paul. I see the nets are also available in Pcbnew under, Inspect > List nets, my list as below.
So my remaining problem is to get my trafo schematic connection numbers to match the footprint.
I will try again to edit a standard component and see if I can accomplish it.
I donât know about your specific âtrafoâ, but in generalâŚ
If thereâs a datasheet for the component and it has pin numbers and pad numbers, you should follow them. Itâs possible to get a symbol/footprint combination working in KiCad but if they conflict external information sources you may run into problems. You may need to adjust the symbol, the footprint or both. In any case I recommend copying both to a personal library as a âfully definedâ component: the symbol in the library has the footprint field populated with the correct footprint.
After the schematic was saved was the net imported to pcbnew?
Or are you just copying the schematic visually?
Just asking because you say you are newby.
Thanks everyone.
Unfortunately not and that I think that was my problem. I wasnât aware how strictly the schematic was followed in the footprint and then onto the pcb. I have gone back to the transformer library and found a better match. That wasnât easy as I had to go through every model that looked like it had the correct spec, my exact model was not listed.
I have now imported that and started to make track connections, fingers crossed.
Yes it was. One of the things I did correctly!
Making some progress but need some more advice please.
The two small downward facing vertical tracks need to terminate in Pads.
Pads are only found in footprints.
So if you want pads, make a footprint first.
âŚAnd that footprint must come from a library, and also be linked in from the schematic to add it to the netlist.
Thanks understood but I have gone through the footprint library and couldnât find anything that I thought would be right. Do you have a suggestion please?
Take a footprint that is somewhat like what you want, and copy it to a personal library.
Then modify it in the footprint editor
Just use a 2 pin connector symbol and 2 pin header footprint, or two 1 pins.
It looks like you have both a symbol and a footprint for the PSU module (U1). Edit the symbol to have two pins (I canât tell on your screenshot of the schematic how you currently have it, but it looks like you used two net labels). Give the two pins unique pin numbers (for example 1 & 2). Then connect the wires from the trafo to the new U1 pins. Edit your footprint and add 2 pads with the same pin numbers with the correct diameter holes for what ever you are using to connect the two boards together. Place these two pads in the footprint in the same relative position to the mounting holes. Use your edited symbol in the schematic and have it point to your edited footprint. Then update the board from the schematic with the correct flags to update the footprints. This way if you need to move the placement of the PSU module the pins will be locked in position relative to the mounting holes.
BTW, looking at your screenshot with the PSU module footprint it looks like you have the mounting holes as just circles in the drawings layer. If you want to mount the PSU module to your board with standoffs (or similar hardware) you should change those circles to NPTH holes with the correct diameter for your mounting hardware.
(Sorry my instructions are vague, I donât have KiCad open in front of me.)
From your second picture it looks that your board already have pads you probably wont your wires to be connected to. So why you want to add extra pads?
That means that you donât understand what is KiCad for. Its main task is to NOT ALLOW you to make at PCB anything that is in opposite to your schematic. If KiCad would not do that main task it would be one more graphic completely useless program. Have that in mind and you will not try to do such things like getting anything form one footprint and trying to put it anywhere else at PCB.
Your schematic is so simple that you can not understand why KiCad donât allow you to do whatever you want as you just can control yourself what should be connected with what.
But imagine when someone has hundreds of connections to be done at 8 layer PCB. KiCads task is to control him in his work after previously he told KiCad what he needs to do using a schematic for it.
OK some progress. As before, helpful comments invited!
All the tracks are on the back surface. 3mm tracks are Mains 230V, 1mm tracks 15V AC
The Mains In connector is 3 pin but the middle pin is not wired or used, this gives the desired clearance between L & N, pins 1 and 3.
Creepage clearance are shown.
Thanks.
Youâve used a big fat clearance for the mains voltage tracks, and thatâs great, but usually there is an even bigger clearance between mains voltages and isolated parts, and those also depend what normâs youâre following, and where you live.
To improve clearances between primary and secondary, rotate transformer 90 degrees anticlockwise and connect the fuse to pin 1and the socket to pin 5.
To do that:
Change your schematic first, update your PCB through tools, then rotate the Tx.
Thank you both.
I am in the UK and I believe we use EU guidelines
Rotating is a great idea but it will push the piggy-back board down. I will have to share Mounting Holes H4 and H8.
One thing (of many) that is not clear to me is; With what I have done so far, does all the copper get etched except for the tracks? What would I have to do to retain most of it as ground plane?
Thanks again, seems a lot better layout.
I can probably shrink the overall board size now.
Also widened the lower voltage AC tracks to 2mm.
This first thing that i see is that on your schematic, you have no pad 1 connected to another pad 1. So your schematic says "do not connect these. Apparently your schematic is wrong. I see lots of issues in fact:
â nothing connected to the 2nd screw terminal. So either connect it or get rid of it.
â no pad/pin numbers on the fuse. You ought to have the screw terminal connected to the fuseholder and the fuseholder to the primary.
â What does âAC inâ represent? And why is it not a component (or at least pads if its a pad appearance)?
All your problems appear to be in your schematic. You need to make it quite precise. If things are in fact not connected, its best to place ânot connectedâ flags on them
Thanks Grant for your comments.
The Schematic has changed since I first posted it and I think, with the exception of pin numbers for the fuse, matches the pcb layout recently posted.
I am using 2 of the terminals of a 3 terminal connector (it is what I have). Not connecting No2 gives me the 230V clearance I want.
It is the output of the on board Transformer, positioned to exactly match a piggy back pcb, which is an already built small linear psu.
