Belt input balancing.

[zOldBulldog]

There are a lot of designs to take uneven belts as input and produce balanced belts on the output side.

But I have not found designs that don't focus on what gets output but rather ensure that the demand on the inputs is even.

I am specifically looking for a balancer that outputs 8 belts and draws exactly the same amount of resources from each of 8 input belts.

Can someone point me in the right direction?

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If anyone is wondering why I would want to do this, it is about unloading multi-wagon trains at high speed. Uneven demand down the line causes uneven drain on the just unloaded chests and after a while you can end up with chests for some wagon nearly empty and the chests for other wagons nearly full... with the end result being that trains have to wait for the last wagon to unload. Very inefficient

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PARTIAL SOLUTION:

I applied Zavian's solution of simply using an 8x8 balancer and it seems to be doing the trick. It appears to be keeping all unload buffer chests roughly equally full if the unload mechanism itself is balanced - regardless of demand.

In my case my usage pattern draws much more heavily from the front belts than the rear ones, but the balancer is doing a very good job of compensating.

Unfortunately, as reported in the thread this seem to be only a partial solution. Circuits can be used by they slow throughput. So, still searching for a solution.

[ScaryBuh]

Your solution is not in the balancer that balances input but rather in coordinate better what goes into your chests of the unloading train. Keep them balanced and when thee chests unloads to a regular 8x8 balancer and all the output is used, your input should also been balanced.

[Zavian]

Actually the traditional 4-4 balancer does both jobs. If the input is uneven, but the demand is even, it will spread the input over all the output belts evenly. If the demand is uneven, it will spread that demand evenly over all 4 input belts. A decent full balancer for any other number of belts should do the same.

[zOldBulldog]

Your solution is not in the balancer that balances input but rather in coordinate better what goes into your chests of the unloading train. Keep them balanced and when thee chests unloads to a regular 8x8 balancer and all the output is used, your input should also been balanced.

The train arrives full, exactly the same amount in each wagon.

If after running for a while the one unload chest is full and another empty,.it clearly has to be because the demand is uneven.

Are you saying that a regular 8x8 balancer will even out the content of those chests?
EDIT: Thanks Zavian, you answered it while I was typing.

[Zavian]

I generally stick to 4 cargo wagons on a train, so that means I can normally get away with using 4 belt balancers. I can take 8 full blue belts from 4 cargo wagons, or 12 mostly full belts. In both cases I split them up into 2 or 3 gangs of 4, where each gang has 1 belt from each wagon, and if they need to be balanced, I run each gang through a standard 4 belt balancer. If I really need balanced load, I'll use a proper split-off from each gang, and then merge the two belts with a balancer. As such I don't think I have ever actually used an 8 belt balancer. (If I need more throughput than my 12 belt unloading can provide, then I'll add another station and have 2 trains unloading, but they will probably each serve a different section of the demand).

So I'd need to actually analyse and test an 8 balancer before I could give a proper answer. Also note there are many different 8 belt balancers around. Many of them are half balancers. They are called half balancers, because you need two of them back to back to get full throughput from any combination of input belts to any combination of output belts. See the examples in viewtopic.php?f=202&t=48258 . Compare those with the 8 belt full throughput balancer from the first post in this thread viewtopic.php?f=202&t=39787 .

I've got no idea how well an 8 belt balancer distributes the demand over the input belts. However if it doesn't do that properly, then I'd either find a better designed balancer, or just drop back to multiple gangs of 4 belts, and split off half of each output from each gang.

[zOldBulldog]

Zavian, I used to do something with similar throughput as what you do and never had the issue I describe.

But I just switched to a.design that could successfully unload16 almost saturated belts from your trains. It is under that kind of strain that what I described happens. With 4 wagon trains like yours it would require 16x16 balancers to keep the unload chests from getting out of whack, assuming those do the trick.

In any case I should be able to test with an 8x8 balancer in an hour or two, and I will report the results.

[quyxkh]

The train arrives full, exactly the same amount in each wagon.

If after running for a while the one unload chest is full and another empty,.it clearly has to be because the demand is uneven.

I think this is not true. Take the usual setup with 12-capacity stack inserters doing the unloading. Few if any items have cargo wagon capacity that's an even multiple of 12, so the last few items in a wagon will always be distributed unevenly. I haven't checked, but my impression is it's always the same inserters getting the odds and ends, always the front ones as I recall. So if you're drawing evenly from every buffer chest and never managing to drain or stuff the buffers, eventually the front chests will be much more empty.

[zOldBulldog]

SOLVED: Zavian's recommendation of simply using an 8x8 balancer did the trick. The unload buffer chests are now staying balanced and trains unload faster.

Edited the original post to reflect it.

[Lav]

SOLVED: Zavian's recommendation of simply using an 8x8 balancer did the trick. The unload buffer chests are now staying balanced and trains unload faster.

Edited the original post to reflect it.

In my experience, that's only temporary. Eventually minor fluctuations accumulate and result in one of the wagons unloading slower than the rest, holding up the entire setup while only feeding 25% of the expected amount. So I generally combine a circuit-controlled unloader plus actual balancer afterwards.

Unloader is pretty simple: connect all buffer chests and you get the total. Divide it by the number of chests, and you get average (offset by a small negative bias). Only unload the chest if it's amount is greater than the biased average, combine all output from a single wagon into 1 or 2 belts, and then feed all resulting belts into the actual belt balancer.

[disentius]

Have not found a good good high throughput balanced train to chest unloading solution yet.
Madzuri's trick (average chests, then stop loaders for chests above average) kills high speed throughput, but guarantees even chest loading/unloading.

I use this lane balancer atm for even chest unloading, found it here:

https://imgur.com/a/sgAsj#lsEagUO

[zOldBulldog]

Thank you Lav and Disentius for the corrections.

Anyone know how much of the throughput is lost by using the circuits? Or if there is a solution that does not kill throughput?

[Lav]

Thank you Lav and Disentius for the corrections.

Anyone know how much of the throughput is lost by using the circuits? Or if there is a solution that does not kill throughput?

Generally unloading only becomes unbalanced when there's unbalanced consumption down the line. So even though circuit-based system will sometimes result in less than 100% unload speed from the buffer chests, it happens at the time when balancer is already half-clogged, and thus no throughput is lost.

Technically if demand is suddenly increased to 100% exactly at this moment then there will be a brief hiccup in output, but I've yet to see this situation in practice.

When there's stable 100% consumption, circuit system doesn't affect performance at all.

[Hedning1390]

I haven't checked, but my impression is it's always the same inserters getting the odds and ends, always the front ones as I recall. So if you're drawing evenly from every buffer chest and never managing to drain or stuff the buffers, eventually the front chests will be much more empty.

Doesn't matter. If some chests gets more filled than others then those chests will slowly fill until the unloading inserters stops at which point the other inserters will get the share. My iron/copper smelters produce full outgoing belts at 3 per wagon and my steel is consuming full ore belts, again 3 belts per wagon. Both are train to train and I can run both indefinitely without experiencing drop in production.