'Universal bus' factory setup

[DailyFrankPeter]

TL;DR: How to handle one belt with many materials on it.

Hi,

I'm looking to get feedback and have someone try this idea too, and share their solutions.

What I'm playing around with is a setup where one main bus ('spine') transports all the items throughout the factory, then specialized sub-factories take a subset of materials, produce a product and return it onto the bus.

Now I have 1 main problem with that:
I'm having to use an imperfect system for loading new products onto the belt. As you can see this is designed to take a surplus of product (of copper in this case) of the bus before putting new product onto it - to prevent clog up. Currently it does that on the basis of removing a 'little bit' faster than putting them on there. Ideally it should only send off new product if some receiver, somewhere, has taken it off - so that the balance is exactly 0 (1 used, 1 added). But there is no way to wire things up inserter-to-inserter - to make an one insert ONLY IF another (which can be very remote) has removed the same item type off the belt.

Even if I wired everything up (added chests somewhere, whose contents can be measured), there are only 2 colours of wires and there are plenty of material types here. Can anyone think of a good solution?

I have to say, bar the fact that the bus needs some manual care right now, to have it not clog up, having just one belt connecting the whole base is extremely flexible and convenient.

[MalcolmCooks]

Is this the kind of thing you're looking for?. It's still limited to how many different items you can have on the belt, but you could relegate the universal bus to take only a few basic materials and have the sub-factories produce items like gears and circuits locally, not centrally.

[DailyFrankPeter]

Is this the kind of thing you're looking for?. It's still limited to how many different items you can have on the belt, but you could relegate the universal bus to take only a few basic materials and have the sub-factories produce items like gears and circuits locally, not centrally.

Haha! Sounds exactly like what I have! And similarly, it get's flooded after exceeding a certain number of item types...

[DailyFrankPeter]

I've solved it actually! And with a hard material limit(**) not a soft one(*), as I call it.

I've wired every producer and consumer of every material type to one extensive red wire system (essentially going everywhere alongside the conveyor belt bus). A wired smart inserter will only throw items on the loop if the (wired) consumers' chest fall below a set limit.

The system never clogs up and at the moment circulates 10 material types throughout the whole base using just yellow belts (it probably could do a lot more, as it flash-fills the bus only when needed, then it's empty again).

Big shoutout to user sillyfly for explaining to me that each circuit system actually has only one map (set of key-value pairs) with all the possible goods (Multiple chests with the same type of goods are summed as one value.) I had thought that a separate wire system is needed for each material, which would've been unfeasible.

The hardest part of all this was understanding the wire system. The interface is too cryptic IMHO, although in principle it works exactly the same as the drone system.

I'll attach some screenshots after the Easter weekend.

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(*) a soft material limit (in the context of a multi-material bus) - a system which relies on yellow inserters filling the bus up a little slower than green ones that are cleaning it (it might still clog up eventually)

(**) a hard limit - a system where producers aren't adding if the consumers aren't requesting - it will never clog up (ideally;))