#How does belt throughput work?

1 messages · Page 1 of 1 (latest)

dense robin
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the game mentions that a red belt can move 30 items per second, but what does that even mean? can someone explain exactly what that looks like?

mystic kindle
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When the belt is entirely full and isn’t backed up, 30 items will go through a tile every second

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15 per side

dense robin
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is there a way for me to use that to calculate how much time it takes to move one item down a conveyor line of a certain length?

mystic kindle
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I mean, yes, but that’s not something that’s ever really useful to know for this game

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You’re never working with just one item

dense robin
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I see what you're saying

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I guess what I'm curious about is the roundtrip time for a set of items

mystic kindle
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Why?

dense robin
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just out of curiosity

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I guess I want to understand how to use the belt throughput concept in a useful way

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the issue I have right now at my base is that I have calculated rates that I have dedicated to particular items

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so for example I'd dedicate a certain amount of iron plates per second to making circuits, another for making engines, etc.

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since the rate of the thing I'm moving is usually less than the belt throughput, I just move it across

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but things change when I start moving it by train

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because then I have to control the rate by splitting the belt somehow

mystic kindle
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It’s useful for knowing how many belts you need to transport the rate of items you want, that’s pretty much it

mystic kindle
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The game gives you backpressure as a tool to never have to think about setting exact rates for splitting things

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If the belt fills up, it stops

dense robin
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what is backpressure?

mystic kindle
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If items hit the end of the belt, they don’t spill off, they just sit thrrr

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So items behind them have to wait on the belt

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And it ends up acting like “pressure” all the way back to where you split off from

dense robin
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so you try to produce less of something if backpressure exists

mystic kindle
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You’re still thinking a bit too actively about it

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You don’t have to do anything to slow down production if the belt backs up, that automatically happens

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How much of the game have you played?

dense robin
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right and I get that. I guess what I want to do is try and not give too much of something rate-wise to something that doesn't need it

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I'm at 80 hours in my solo world

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and 40 into a coop world I believe

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have yet to launch a rocket

mystic kindle
dense robin
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I'd like to explain a scenario in which it does

mystic kindle
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If it can’t eat it that fast, the belt backs up. If it can, eventually the output will back up and then the input backs up in response

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Any scenario where it happens is temporary until the belts fill

dense robin
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I get that but think about this for example

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let's say I bring iron plate out of a train at a rate of 30 per second, meaning I use the whole belt

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and I want to dedicate some of that iron towards making circuits and engines

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I don't want to dedicate the whole line just towards making circuits or engines

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30 per second is too much for just circuits if there's other things that want to use that line

cedar wolf
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is splitter with priority towards circuits/engines not solving the case?

mystic kindle
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This is precisely the scenario I described though

dense robin
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I typically use splitters with priority for this sort of thing

mystic kindle
dense robin
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but then the issue I get is that I'd have multiple splitters with priority across the belt and I have to make sure that things back up that far just for that to work

mystic kindle
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Which they will

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Unless you’re storing tons of stuff in chests for no reason…

cedar wolf
dense robin
mystic kindle
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A single passive provider should be fine

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Usually when people don’t “get” backpressure it’s because they’ve never seen it because they hoard things in chests for no reason

dense robin
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the reason I worry about this sort of thing is I don't want to pollute too much when it comes to producing ore

cedar wolf
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it is best to put passive providers on lowest priority belt branch

dense robin
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but the fact you have to worry about priorities in the first place is what can get things out of hand

mystic kindle
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If you’re that worried about priorities then I think it’s a sign you don’t have enough production to adequately supply everything

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Like, there’s something going on here if it’s that big of a concern

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A screenshot would be helpful at this point

dense robin
dense robin
mystic kindle
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Yeah production is the issue

mystic kindle
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Or take the fight to them

dense robin
mystic kindle
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If you’re not playing a deathworld then being that deathly afraid of pollution is just getting in the way

dense robin
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I agree

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I guess what I want to do is just dedicate and exact rate to the things I supply

mystic kindle
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Micromanaging things that closely is not going to be easy

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It can sorta be done with a circuit to rate limit the belt

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But again, the game already does that for you

cedar wolf
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yeah, it's not really worth the effort

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build bigger, massacre bugs and enjoy the game

dense robin
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sure

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I see what you're saying

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I'll give what you guys are recommending a try and see if it works out

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thanks for the advice

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I guess while I'm at it though, don't you guys at least try to figure out the exact ratios of things when made

mystic kindle
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Eh

cedar wolf
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i do - but it always measured in whole amount of fully working assemblers

mystic kindle
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Within a given production block, yes

cedar wolf
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so no micromanagement

dense robin
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right

mystic kindle
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It depends on the goal

dense robin
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but differences in these things do matter

mystic kindle
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If this is a “starter”/mall base, then I’m not trying to dial in exactly how much plate production I need because I’m going to need more lager anyway

dense robin
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no I know but sometimes you scale a little bit ahead if you know what I mean

mystic kindle
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Exactly

dense robin
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like advanced circuits are made at 4 times the rate it takes to make blue science

mystic kindle
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So you overbuild production

dense robin
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so you can overbuild advanced circuit assemblers and waste space if you don't do it right

mystic kindle
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For some context, this is a base where I was purposely trying to not overbuild like I’m mostly used to

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Hold on, clipboard broke

dense robin
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nw

mystic kindle
dense robin
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that looks beautiful

mystic kindle
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Much more forest but still

cedar wolf
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like here it shows 2.5 gears assemblers, but making it 3 is a ok

mystic kindle
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Yeah if it’s not a megabase, trying to micromanage production that hard isn’t helpful

dense robin
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right

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I think what got me interested was when I was trying to do some math to figure out how much I need of everything down the line to make a certain amount of blue science a second

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I realized that if I rounded at certain points and stopped the overproduction can be quite bad

cedar wolf
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exactly 1 yellow belt of iron, no waste here too

dense robin
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that's pretty neat!

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I want to figure out how they do that

mystic kindle
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You can do the math without rounding up at each step

dense robin
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yeah that's usually what I do

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I try to leave the rounding to the end

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or to where it'd be reasonable

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thank you guys so much for bearing with me on this @mystic kindle @cedar wolf

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and sorry for being pedantic

tidal ether
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The items per second limit of belts comes from the length of an item on a transport lane and the speed at which the transport lane moves. A belt has 2 transport lanes and if it is straight these can hold exactly 8 items. This means each item has a length of exactly 1/4 tiles. If a belt moves 1 tile per second it can move 8 items across a tile per second, the maximum throughput of the belt.

As belt speed increases, fewer items need to be on the belt to achieve the same item per second count. This can be tricky to visualise since a compressed yellow belt with 8 items per tile (4 per lane) will turn into a red belt with 4 items per tile (2 per lane), half the density, while throughput remains the same.

As far as planning goes, you need to make sure that the sum of production going onto the belt or consumption trying to be removed from the belt does not exceed the belt item per second count. If this happens, then some production buildings will either not be able to unload their product onto the belt, or will not get the inputs needed to operate.

Splitters have a theoretical throughput of 2 belts of the same tier. The exception is if one of the outputs is blocked up in which case total thoughput will be lowered by how much that output is blocked up. This is especially a problem when dealing with spliters running in filter mode since if the same item appears on the same lane of both inputs at the same time, the output is blocked causing reduced throughput. For this reason using a splitter to filter 2 belts with two different item types mixed equally together the result will be significantly less than 2 belts of throughput. This can be an issue when dealing with some mods that have recipes output an assortment of different items that you may place on the same belt.

mystic kindle
tidal ether
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Partly, and did not see people explaining that items have a length, which to me is the most confusing part about how items per second work.

mystic kindle
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It’s not needed to understand it at all though, and the conversation actually went toward “micromanaging belt throughputs means you’re probably doing something wrong”

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You can certainly calculate an item length, but that’s not helpful whatsoever

dense robin
dense robin
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instead of using a splitter

mystic kindle
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It’ll still only be half throughput if both input belts were full

dense robin
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right but then you wouldn't want to merge them

frigid pasture
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It's only typically an issue if you are dealing with mixed ore and are filtering it to put it on separate belts, in which case throughput isn't much of a problem because it's just one belt of ore and a mild temporary slowdown. For most anything else you should never have different items in the same lane of a belt

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If you're doing some sort of sushi belt base, or use science belt sushi, maybe you'd run into it there too, but sushi bases are not exactly made for high efficiency

tidal ether
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The problem mostly shows up in mods like pyanodons where a lot of recipes output 2+ different items. If you unload these onto the same belt and try to push belt throughput limits you can run into filter splitters becomming the bottleneck when trying to finally separate the product to be more useful. In such case I find the solution is to use a filter splitter per belt and then merge the resulting belts using additional splitters. The expanding and then reducing avoids any potential throughput bottlenecks from the filters on splitters.

dapper spruce
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I recommend the rate calculator mod to help made sense of things. You can select some machines or miners, whatever and it will show you the items/sec provided or needed. Basically if you want things operating at maximum efficiency, giving your machines enough items/sec or allowing them to output enough items/sec onto a belt is pretty important. https://mods.factorio.com/mod/RateCalculator

Factorio Mod Portal
Rate Calculator - Factorio Mods

Calculate maximum production and consumption rates for the selected machines.

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For example, if you want 30 items/sec of copper coil, and one machine outputs 15 copper coil/sec, you'll want to use 1 red belt or 2 yellow belts, one machine for each side of the belt for red belt or 1 machine per belt for yellow belts. maximum efficiency (the machines are always going to output their maximum if all of the copper coil is being used and the machines always have copper plates and an empty belt to place onto).

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The other factor is how do you insert onto the close and far side of a belt? For that, you can either use bob's adjustable inserters mod or just realize that you can only output 7.5 items/sec (for yellow belts) since the inserters only put items onto one side of the belt. You'll have to combine your resources making one full belt to actually get 15 items/sec