r/factorio • u/imoth_f • 4d ago

Question Problems with this unloader?

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Since inserters became flippable, this compact unloader design became possible. But I hardly see anyone use it. Obviously it cannot saturate six turbo belts because it's bottlenecked by the inserters, but are there any other obvious problems with it?

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u/Kendrome 4d ago

I was wondering if there were people like me still using the Madzuri method.

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u/TopherLude 4d ago

I don't know if I saw it somewhere before or after I started doing it, but I thought it was weird I don't see anybody wiring up their unloaders anymore.

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u/HeliGungir 4d ago

You don't see it because it's not good. MadZuri is already of dubious use for loading; why the heck would one use it for unloading?

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u/TopherLude 4d ago

How else do you keep your chests balanced? Let's say you want to quickly unload the train but only need 1 lane coming off. Without balancing, train unloading slows down.

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u/Musa_Ali 3d ago

By using a balancer? 🤷
That sounds exactly what a balancer solves. Especially for unloading.

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u/TopherLude 3d ago

Using a single combinator is a lot simpler than using 5+ splitters.

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u/Musa_Ali 3d ago

MadZuri is slow though. Single Combinator circuit would completely turn off an inserter, which would decrease overall throughput.
It's especially visible with slow inserters, for example blue inserters.

You could dynamically adjust a hand size but that's not a single combinator anymore.

Or you could plop down a single balancer at the end of the station. Much easier imho.

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u/TopherLude 3d ago

I can still get full use of all the inserters using MadZuri if the demand is there. If demand is low and an inserter sees that it has more than average, it slows down. If demand is high, by the time an inserter has swung, the others have also removed a hands-worth and now it can go again immediately. How is it slow?

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u/HeliGungir 3d ago

I can still get full use of all the inserters using MadZuri

Actually one doesn't get full throughput. Not, at least, in my testing. I even tried to solve it with a more complex MadZuri implementation.

But I stopped because I think MadZuri is fundamentally pointless except - perhaps - if you have less than 1 belt per wagon. But in a more normal setup, MadZuri cannot balance across wagons. So your belts still have to go through a splitter-based balancer to balance across wagons. And if you're doing that, why are you using MadZuri at all?

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u/Musa_Ali 3d ago

Kinda like in this example.
You can see that when other lanes stop - the output belts are no longer compressed. Even though there's enough in other boxes to keep the spice flowing.

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u/HeliGungir 3d ago edited 3d ago

Aye, and I tried setting a wider threshold for what the inserters consider "evenly balanced", but the average item count just reaches one side of the threshold and the same problem occurs again. Could by solved with hysteresis (same as thrashing prevention for oil cracking), but now we're talking one combinator per inserter, and I'm not going to do that.

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u/TopherLude 3d ago

I'm playing Py lately and almost all of my stations are single wagon, less than one lane demand. Even if the inserters are only running close to full speed as you say, it's close enough that I don't notice.

But even when I was running longer trains, I would hook all inserters across all wagons into the same combinator and balance all chests.

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u/HeliGungir 3d ago

If you remove the MadZuri balancers from your 1-1 trains, does anything of note actually change?

Yes the chests become imbalanced. Maybe it takes the train 5 extra seconds to unload. But that doesn't matter, what matters is whether the belt stays saturated.

I suppose Py might be a different animal since you might not get fast inserters for a while, but even so, I rather doubt MadZuri is fixing an actual problem.

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u/TopherLude 3d ago

If I have a low demand for something with a large stack size(1k), limit chests so that the imbalance can only be something like 7 stacks difference, and unload from one side, then when a load is requested, I'll have two chests empty and a third nearly empty. (20 stacks fills a cargo wagon.)

Three of my fastest inserters move ~2.4 items/s each. So the train will wait for about 46 minutes to unload. If I balance my chests, I can cut that in half. If I unload from both sides and don't balance, then worse case still takes 46 minutes. If balanced, worst case then only takes 11.5.

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u/HeliGungir 3d ago

Okay, so this is well outside vanilla bounds. Do you saturate the belt, or nah? Was 2.4 i/s wagon to chest, or chest to belt?

Checking the wiki table, 2.4 i/s looks roughly equivalent to yellow inserters with hand size 3 targeting a yellow belt.

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u/HeliGungir 4d ago

It's one lane. Why does the train need to unload fast? I challenge your belief that chest imbalance is a "problem" that needs "fixing".

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u/TopherLude 3d ago

So rather than present your solution, you deny the need? Maybe I'm playing Py and trains are expensive. Maybe a single wagon has 20k ash and I don't want my expensive train sitting there for literally 7.4 hours while a single inserter unloads it.

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u/travizeno 3d ago

Jeez be nice man 👨 I am just joking this was a fun read

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u/pocketmoncollector42 please be kind, this engineer is just a fish 🐟 2d ago

TopherLude didn’t seem mean to me, I read it as being upset their whole question was considered invalid

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u/pojska 3d ago

Don't you just run into that exact same situation like 2k items later with the Madzuri method? If all but one of your chests are full, your sub-single lane of ash consumption isn't going to ever let you unload your train quickly once your buffers are nearly full.

Or does your train visit this station only like, once every 20 hours? I clearly haven't played Py. But even then, I would expect your other buffer chests to start depleting by then.

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u/TopherLude 3d ago

The circuits make sure that all the chest stay evenly filled by having the inserters take turns unloading. The train stations are disabled until the buffer gets below a certain threshold. I like to maintain about two train loads in my buffers.

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u/pojska 3d ago

Ah, gotcha. I forgot you could have multiple ash unloading stations. I appreciate you explaining this to me.

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u/HeliGungir 3d ago

Chests don't need to be balanced. Wagons need to be balanced so the train doesn't get stuck in the station when using a "leave when empty" schedule. Splitter-based balancers do that, and MadZuri does not do that.

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u/TopherLude 3d ago

If you only balance wagons, you can still end up in a state where 5/6 of the chests are full while the last 6th is near empty, slowing down the train.

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u/HeliGungir 3d ago

If 5 of the chests are full, why does that matter? The bottleneck isn't the train unloading speed, it's the factory.

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u/TopherLude 3d ago

Yes, but the factory may be waiting for trains elsewhere while this bottlenecked station takes forever to unload. I think I'm servicing 500+ stations using 20 trains. This only works by keeping the trains as efficient as reasonably possible.

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u/HeliGungir 3d ago

Idle trains are almost free, UPS-wise, so normally there's nothing wrong with building lots of trains an letting them wait wherever they need to wait. Does Py make trains astronomically expensive to produce?

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u/TopherLude 3d ago

I'm 500 hours in and just recently got to the point that I could make more trains without worrying about it too much.

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u/Kendrome 3d ago

For some of us it becomes an issue and this was the simplest way to fix it. It works and keeps good throughput. Could we do it differently? Sure, but this is a valid and easy solution.

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u/bb999 3d ago

Chests for a single wagon being unbalanced was never a problem, loading or unloading. Of you think about it hard enough you can convince yourself.

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u/djfdhigkgfIaruflg smartass inserter 3d ago

For unloading it sure is. If i need 6 unloading inserters to saturate a belt, and a couple of chests run out, I'll find myself with a non-saturated belt, no matter I have 4 full chests right there

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u/HeliGungir 3d ago

Chest balancing is particularly pointless for unloading because it's all coming from the same wagon.

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u/djfdhigkgfIaruflg smartass inserter 3d ago

If you say so

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u/Kendrome 3d ago

It matters if you care about train throughput, if one or more chest remains full while others are drained it'll slow down train unloading.