This factory can produce all vanilla level 3 module types, but will only produce one module type at a time. Those modules will be produced at a rate of 10/min. It will try to keep 1000 Productivity, 1000 Speed, and 200 Efficiency modules in stock. It will only produce the modules it is currently shortest of. It will turn off any factories not being used, and it will turn off all factories when the targets are reached.
You will have to manually disconnect any copper/power wire connection crossing over a blue belt.
I'm pleased with the circuit logic here for figuring out what needs to be produced. I knew that three comparisons would produce a full ordering, and then the trick was to figure out which comparison result combinations should trigger which module type. It has a small bug right now that might require you to drop one level 3 module of any type into one of the chests.
Also, express belts are used to carry the modules. These are not for capacity, but for latency, to reduce the time between the modules being produced and being counted.
This blueprint works fine in 0.17.