How to use KiCAD to create wiring diagrams?

While a schematics capture application is more targeted for PCB circuits, it can also be great for wiring diagrams. Here are some tips to get the most out of KiCAD for that purpose:

  • Wires cannot be annotated with name/value pairs in KiCAD. But you can create a point-type “wire meta component” yourself, maybe looking like a small dotted circle line. You can then place it as the center of every logical wire, and connect its both pins to the pins of connected devices. Now you can add meta information to your wire, and also display these as fields in the logical middle of your wire: wire color, crosssection, cable type, special requirements for chemical and heat resistance etc..
  • KiCAD will display all wires in the same color. So in case you rely on wire color for wire identification in your project, the resulting wiring diagram will be hard to read for (visually) for working with your physical project, even though the wire color can be displayed in a field (see previous tip). For that reason, better use wires only to encode the general role of a wire (like red for all positive power supply wires, black for the negative ones). And rely on wire ID numbering for identification purposes. There are many commercial products for adding these numbers to your wires also after installing them (like cable flags, or as a more durable solution, cable ties with 10×2.5 mm label field). You can add these wire identifiers to the fields with the pin descriptions of your components, maybe using a vertical bar “|” to separate wire ID and pin name / number, and place the wire ID on that side of the field more to the edge of the component.
  • Even if KiCAD could display different wire colors, wire IDs would still be needed if you use buses, because a bus could contain two wires of the same color so that tracing them in the diagram would be impossible. And you should use buses, they are a great means for tidying your wiring diagram up optically. Especially, use buses for all multi-core cables in your application, as these are a sort of “physical buses” anyway.
  • Use the KiCAD “Edit -> Find” functionality to find dsired elements in your wiring diagram quickly; this adds a good deal of interaction to your diagram. You should design your IDs for wires and components, and everything else that appears on labels in your physical product, in a way so that every such string is unique. This makes searching through the diagram more comfortable, as you know that the first (and only) result is the one you are looking for.
  • Look through kicadlib.org to see if you can locate useful components not already in your locally installed KiCAD libary.

 


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