How are you labelling the 12V_1 … wires?
Do you use the “T” function or is there another function to use?
Note how on his examples the (for example) “12V_1” is black text. Where your notes are in blue text. The blue text are text notes, but the black text are local labels. (See my previous post about how to apply the different types.) What he did is have the label connection point directly on the pin ends. This is another way to use local labels (in addition to the method I described above).
Even if you have wires connecting two (or more) pins together, also adding a local label does two things. First it is annotation on the schematic for a human reading the schematic to know what that wire’s purpose is. Second, when working on the PCB and deciding on which traces to have wider (for example to increase the current carrying capacity, like choosing a thicker wire gauge) then you know what the net name will be. Otherwise the net will be named (seemingly randomly) based on one of the pins on the net. I know this probably sounds confusing right now if you haven’t laid out any PCBs yet, but believe me when I tell you that strategically adding labels will make setting up for laying out the board easier.
Okay before I proceed then, the text I have placed on the opposite side of the connector as sort of like a description is okay at this point? I just want to make sure I am moving forward now.
My next step would be to take out junctions and put text in place of them at each connector it joins to?
This is confusing but you are taking the time to explain it in a fashion that for the most part I understand. May have to read it again but I will get it.
Use a version control system (VCS), for example SVN or git.
I’m not confused enough now??? LOL
Not necessarily. The primary goal for a good schematic should be readability. It is easy enough to follow the “wires” on the schematic as you have it at the moment.
If the design is changed to labels, then a person reading the schematic will have to first find every other instance of the first label to understand what the circuit is doing. Just because one can add labels to every connection and remove the wires does not mean that one should.
In the example I provided above, no real loss of readability exists when changing those certain nets from wires to labels.
As @SembazuruCDE mentioned,
When you go to layout the board you will understand this forward thinking in the design process.
I typically “Archive” the entire project with the Julian date and 24 hour time.
The file would read, “ECM Trainer_19004_1300.zip”.
Okay two questions,
Am I ready to move on to the next step?
How do you “Archive” the project? Sorry I am sure this is an easy question but …
Okay I think I archived it. It went to a .zip file, Correct? I guess that will save a lot of space. Okay what’s next?
From what I can read (the text is scaled down to near unreadability in your posted screen capture) It looks good. The real test is after you have put this schematic away for a year or two (or in my case a week or two), then come back and are you able to understand what the expected design intent is?
You don’t have to remove the green wires when placing labels. Some people like to to try to reduce the spaghetti effect, but your wires don’t seem that spaghettified. My problem with schematics done like what Joan demonstrated (the screen capture with the black background way up in this thread) is it can be difficult to see the relation of what signal goes where, especially if it goes multiple places (like what I think might be CAN bus signals in your most recently posted schematic). For me, leaving those lines there and then adding labels (CAN_HI and CAN_LO, spaces are invalid characters for labels) to the wires allows me to easily see on the schematic that they are common to 3 connectors. But, also when laying out the PCB that I should probably route those two nets as parallel to each other as I can.
For redundancy, not only would I put labels on the nets but I would leave the wires there. You can put multiple labels on each wire, but it is advised to use the same label in those multiple places for each wire. KiCad won’t complain if you put (for example) “CAN_HI” and “CAN_PLUS” on the same line, but only one of those two labels will be chosen when sending to the PCB. Which one will be chosen can seem a little random, but probably has to do with which label object comes first in the internal data model of the schematic.
Oh, the sample net names above are all in upper case not because they have to be in KiCad. But simply to help separate them from the surrounding text this post. If you use mixed case for your nets, watch out. KiCad may or may not be case sensitive. For consistency’s sake I wouldn’t test it and make sure you use the same case for your labels. The easiest way that I’ve found is to place (and write the label name) the label once, and then copy that label object to other places on the schematic.
Even just a little amount of programming knowledge should be enough to understand the difference between a comment and a variable name. 
Do I label all of the wires or just the common ones such as CAN etc?
Do I label say, the wire from the relay to pin 70 of the ECM and if so, what do I call it? ECM SW GND?
Is there a better way to put images on here than screen dumps?
When I have put all my labels on, is it ready for next step?
Once your connections are all sorted out you need to think about your connectors. You need to think about what type of connector is appropriate - for example is it something that will be repeatedly plugged in and unplugged by the user? Does it need to be vertical or flat to the board? Does it need to be vibration proof? The connector will need to meet the voltage and current spec which I think you mentioned earlier. You can use any of the major electronic retailers websites and they offer a variety of filtering options to narrow down your selection. Once you have decided what is the best option, you need to determine if there is an appropriate footprint available either within the standard library or elsewhere. If you are on a deadline, it might be sensible, if there are compromises to be made, to choose something using a footprint that already exists within the standard kicad library as this will remove a significant extra piece of work.
You are making good progress - there are some potential bumps ahead but you can work though them and with a bit of persistence I am sure you will have a very serviceable design laid out pretty shortly.
Thanks John, you guys have been very patient. Much appreciated. It has been a steep learning curve. Now I know what I put my students through lol.
Do you or anyone else have any suggestions for these connectors? They will not be plugged and unplugged very often if at all, I would like 90 degree to keep the board low profile in case I want to add onto it, there is no vibration or heat and the voltage and amperage specs were posted above but this is what I think.
Power source = 13.8VDC and 15 Amps
Relay = 15 Amps on the load side and less than an amp on the control side
Switch = <1 amp at 13.8V
CAN LINES <5V < 1A
All others should be same
Is anyone here on the weekends?
And now, Kicad.info forum presents to it’s users the word of the day!
noun Physics, KiCad
- the theoretical stretching of a users mind as it encounters extreme differences in wiring angles, especially those that will be later associated with PcbNew.
I am officially spaghettified. My brain hurts.
Okay so here is my latest version. A long way from the beginning but starting to feel more comfortable. Many thanks. Is this too much now or are we ready to turn this into a PCB. Like to hear a couple of comments if possible. Cheers
Blue Color — Are commenting your schematic only
Green Wire – Presenting copper trace/net connect between each pin/pad of each symbol/footprint/part
Red – Present symbol/part with set of connectable pins/pads
Black Text – (In your case are optional) use to naming a net (green wire). It often use to tell the software the twos or more disconnected green wires with the same net name are physically/electrically connected.
Your current problem is that some of the black text did not place on the green wire correctly (where you see the small black square are). Also, I usually not place more than one black text on the same green wire to avoid I making a dump mistake (make same net have more than 2 names, and also mean all the net have those two names are treated as same copper trace electrically).
So i would said for your case, just remove all of them - Then you can run ERC, then ready to to layout actual board. You should play with the net label (black color text) later when you understand what you doing.
1 Like
Also why all your symbol are J*B? It mean your only use half of the physical connector pins. If that is not intended, you should use the right symbol that only have 1 part so you can map it correct with physical connector when you doing layout.
Digikey has been extremely supportive of KiCad in the past. I think they are also one of the first sponsors for the first forum convention that is upcoming; early this year.
A really big issue with designs is what one can currently “add to cart” to populate the finished board. It is my recommendation that one uses Digi-key to find and order parts to use.
1 Like
Do not do this!
I know you mean well, but this “do not use 4 way connections” stuff can get annoying.
Let others create their schematics in the way they like. You can tell them that there is an alternative and list its benefits but simply stating “do not do this” really does not cut it.
1 Like