Right, initial thought is that we set up a new category ... "Processor controls and instrumentation".
Within that we can have various pages, but the primary one would be ... "Processor control schematics", as Alistair suggests. This could contain a range of wiring diagrams covering the simplest to the most complicated, perhaps, in time, even Logic relays and PLCs. All of the components mentioned on the schematics will have dedicated pages explaining as much as possible about each item.
Tony ... would it be possible to have specific areas of Alistair's schematics acting as links to pertinent pages? I have vague recollections that this was possible with a very old part of CorelDraw, but I could be wrong!
We already have Keith's (he's been quiet the last few days!) float switch page and Tony's level/pressure switch page that could be moved to the category.
I think a Noddy's guide to controls, page would be of great use too those not too familiar with the discipline, perhaps a rewrite of my post with the 230v control circuit.
I love the idea of the automotive pressure switch, especially as it's from a Land Rover! I've got an old, adjustable, industrial switch on my processor (not that I've got round to wiring it up yet!) so I think we need to cover all possibilities for all components, so perhaps wiring schematics need to simply say "pressure switch" rather than being specific.
Just my suggestions.
Open to any other thoughts.
If no objections, after a couple of days I'll create the category (if I can remember how!) and move the pages as a start.