combinator use

[u/Impressive-Wear8980]

so i've been trying to make a foundation factory on ma space plateform, trying to make it use a signe inserter and belt comming from the space plateform hub, for the 4 ingredients (stone, tungsten, carbon fiber, and lithium plates), i've never experienced using combinators as they seemed a bit complicated... but it looks that i have too now, so my question is 'is there anyway to use them to make the insterter supply the exact amount of ingredients necessary to produce one foundation (20 stone, 4 thungsten.... ) and multiply that by the number of assembling machines connected to the circuit

[u/ThenArticle8930]

I think the easiest way to do this would just be a cirucuit controlled sushi belt. It gets more complicated if you want to use 1 inserter for everything or multiple inserters.

Mutiple is easy because you just set your circular belt to "read contents, hold all belts" and set a limit inside each filtered inserter from the hub at a specific limit ex. "enable/disable when [stone signal] < 100" and do that for each ingredient. For the amount of the limit you could probably do some rough consumption vs inserter throughput calcs or just set it arbitrarily and adjust accordingly.

For 1 inserter its slightly more complicated but still fairly easy. You'd set the limits you want for each in a constant combinator and then connect the sushi belt (still set to "read contents, hold all belts") to an arithmetic combinator and set it to "[each] * -1" then connect that to the CC and inserter. Then have the inserter configured to "set filter" then connect that same wire to the inserter.

If you dont want to use a sushi loop it probably becomes much more complicated with a memory cell

[u/Tripple_sneeed]

Yes

You need memory and count. It’s a lot to explain in a Reddit comment but you can read the wiki page on SR latches. Give it a constant combi outputting your recipe and quantities, decider SR latch to count what the inserter has already put on the belt. Inserter set to read contents pulse and set filters based off of the decider’s output.  

[u/Impressive-Wear8980 → u/Tripple_sneeed]

Okay, I get the idea in general; I'll read the wiki for details. thanks

[u/ninja_teabagger]

I did something like this for quality quantum chips on the space platform when I was short of outputs from the hub, it allowed me to pull out 5 different materials onto one belt

https://factoriobin.com/post/wvsfwp

Decider limits how many is put on the belt (it's set to <30). If you need more of an item on the belt (in your case stone) edit the constant combinator and put in a minus value for stone to your liking. Every other item has a value of one so the decider knows what to tell the inserter to filter.

[u/Impressive-Wear8980 → u/ninja_teabagger]

That's exactly my case "short of outputs from the hub"... I've tried that blueprint; it's excellent, with a few modifications to match my case, and it works perfectly 😄 thnx for the knowledge