Logistic Buffer chests - why?

[seePyou]

Hello all,

I do not know if I'm alone in my puzzlement, I may very well be alone in this. I do not get the point of the logistic buffer chests (buffer chests from now on).

I never remember needing them when I was playing before, and I still do not see the point in them now.

Use case 1 : Player requests.
If they were the only way to fulfil these requests that might be something, yes. But the player is not solely receiving items from buffer chests. If another provider (passive, active, or even storage) is near the player, the bots will go to this chest and then to the player.

Use case 2 : Construction requests.
Cannot extend the construction without merging the logistic networks (which was the point I believe at some time) as the buffer chests are not fulfilled / serviced if placed outside the logistic zone of the roboport.

Use case 3 : Remote operation requests.
Defining this as "I have a wall of flame turrets and I am sending them barrels of fuel, removed from barrels with an assembler there." Well... why a buffer chests and not a requester? Same job, and there is no specific benefit I can see in using a buffer and NOT a requester. The barrels in the requester will then be taken out by inserter and into the assembler, just like it would with the buffer.

Use case 4 : Bridging the logistic networks.
Again I do not see how this is possible; the buffer chest needs to be in the logistic zone, so it cannot bridge networks. Even if we say that they do bridge the networks by making the networks not touch, and placing two buffer chests (or one buffer and a provider) on the edges, connected by inserter, I would argue that the same job is met with a simple requester.

These are just what I heard people say; maybe there is something else too. But in every case, I cannot see why I should use, or would benefit from using, a buffer chest.

Can anyone present me a use case or correct some mistaken assumption I may have and thus make a use case viable?

[Manron]

They are very usefull to prevent loops in the logistics network.

if at any point you have a requester chest output to a belt and a provider chest taking from the same belt, your bots will start moving items in an endless loop. replace the provider chest with a buffer chest and make sure the requester is not requesting from buffer chests, then there will be no loop. but still the bots can pick from the buffer and deliver stuff to where it's needed, be it a player, a construction site, or requester chests that are set to request from buffer chest.

those loop-issues were very hard to overcome before, usually requiring to built a seperate logistic network or use some combinator (black)-magic.

[urza99814]

I've had problems in the past that a buffer chest might solve... Basically i had wood set to auto trash, and wanted to then use that wood to fuel my train network. So, you have the train stop request 2k wood, set your auto trash, and go cut some trees. But once you build more than one train stop you have a problem -- all the wood goes to the closest stop and the rest get starved. So you reduce the request to 100 wood at each station, but then they fill up and your trash slots don't work because there's nowhere to put it. So then you try to use requester/provider chests to create centralized storage, but instead of feeding the trains you end up with bots pulling from one end of storage just to put them back in! And soon all your bots are trapped in that loop. But if you use a buffer chest it should break that loop (AIUI... Haven't needed them in my current base as I'm not really using any bots)

[Aeternus]

They are also handy for seeder factories. You know, the part of your factory where you build structures to expand.
- Connect circuit network between inserter feeding into buffer chest and said buffer chest. Inserter active only when everything <40
- Buffer chest set to demand 400 of that type of item.

When you deconstruct buildings, they go back to this seeder factory, ready to be re-used, or consumed (in case of yellow/red belts)

They are also handy for setting up defense repair/replacement supplies close to a wall/defense section to shorten construction bot travel time

[eradicator]

Another example:
Put some preconfigured buffer chests into your solar blueprint. Bam. Your logistic bots are now carrying the bulk of the solars/accus and the construction bots can concentrate on actual construction. And a logistic bot with full stack bonus carries 3 times more items than a construction bot, so they're faster too.

[Kelderek]

They are also handy for seeder factories. You know, the part of your factory where you build structures to expand.
- Connect circuit network between inserter feeding into buffer chest and said buffer chest. Inserter active only when everything <40
- Buffer chest set to demand 400 of that type of item.

Doesn't a filtered storage chest accomplish this same idea already? For example, you have an assembler making electric mining drills, an inserter with a logistic condition moves them into an uncapped storage chest with a filter for electric mining drills. If I were to go tear up a spent mining outpost and return to base and throw my extra drills into a logistic trash slot they will all be moved into this storage chest because of the filter. I suppose the buffer chest would be more useful in that scenario if you expect to have more than a full chest in your entire network, but that is less common for a lot of factory building items.

[seePyou]

They are very usefull to prevent loops in the logistics network.

if at any point you have a requester chest output to a belt and a provider chest taking from the same belt, your bots will start moving items in an endless loop. replace the provider chest with a buffer chest and make sure the requester is not requesting from buffer chests, then there will be no loop. but still the bots can pick from the buffer and deliver stuff to where it's needed, be it a player, a construction site, or requester chests that are set to request from buffer chest.

those loop-issues were very hard to overcome before, usually requiring to built a seperate logistic network or use some combinator (black)-magic.

Please understand that I'm not disrespecting you with the following, I'm just trying to discuss it openly as I do not understand.
I dispute this solution, as not effective design. You ask too much of something that was never and should never, in my opinion work. I would never connect a requester and a provider chest with the same belt, exactly to avoid these loops. Furthermore, I see no point in this belt connecting them. I fail to see why a provider chest would be taking things off a belt that a provider chest was outputting. If you are going for "overflow", a) you don't need it, and b) you can use a storage for this. What is the exact need or scenario where such a belt connecting these two solves?

[seePyou]

I've had problems in the past that a buffer chest might solve... Basically i had wood set to auto trash, and wanted to then use that wood to fuel my train network. So, you have the train stop request 2k wood, set your auto trash, and go cut some trees. But once you build more than one train stop you have a problem -- all the wood goes to the closest stop and the rest get starved. So you reduce the request to 100 wood at each station, but then they fill up and your trash slots don't work because there's nowhere to put it. So then you try to use requester/provider chests to create centralized storage, but instead of feeding the trains you end up with bots pulling from one end of storage just to put them back in! And soon all your bots are trapped in that loop. But if you use a buffer chest it should break that loop (AIUI... Haven't needed them in my current base as I'm not really using any bots)

Please understand that I'm not disrespecting you with the following, I'm just trying to discuss it openly as I do not understand.
There is a basic mistake in logic here, in that you have created a need of a material that is limited and is not "built". You call the lack of wood in a station "starvation" when I would call it "good use of wood". I would never build a station to run solely on wood, but I would want to build a circuit condition in the loader that would take wood if available and stop the coal/solid fuel/rocket fuel, as to use the wood I produced, when I produce it. When there was no wood, this is not "starvation", but the wood having been used as I planned, and now the trains can flow again powered by the things they were meant to be powered by.

[seePyou]

They are also handy for seeder factories. You know, the part of your factory where you build structures to expand.
- Connect circuit network between inserter feeding into buffer chest and said buffer chest. Inserter active only when everything <40
- Buffer chest set to demand 400 of that type of item.

When you deconstruct buildings, they go back to this seeder factory, ready to be re-used, or consumed (in case of yellow/red belts)

They are also handy for setting up defense repair/replacement supplies close to a wall/defense section to shorten construction bot travel time

Please understand that I'm not disrespecting you with the following, I'm just trying to discuss it openly as I do not understand.
Your second argument of defense repair "defense repair/replacement supplies close to a wall/defense section" is easily accomplished by requester chests. I do not understand why a requester chest for this use is worse of ill-fitted to the task.

As for the circuit network, I do not exactly understand how you have planned this. Can you elaborate? I think this is some kind of bridge and trash in one, so it sounds interesting, but I do not get it now. Can you describe it in more detail?

[seePyou]

Another example:
Put some preconfigured buffer chests into your solar blueprint. Bam. Your logistic bots are now carrying the bulk of the solars/accus and the construction bots can concentrate on actual construction. And a logistic bot with full stack bonus carries 3 times more items than a construction bot, so they're faster too.

Isn't this accomplished just as well by a requester chest? What would the requester chest do that is worse and a buffer is preferred?

[eradicator]

Another example:
Put some preconfigured buffer chests into your solar blueprint. Bam. Your logistic bots are now carrying the bulk of the solars/accus and the construction bots can concentrate on actual construction. And a logistic bot with full stack bonus carries 3 times more items than a construction bot, so they're faster too.

Isn't this accomplished just as well by a requester chest? What would the requester chest do that is worse and a buffer is preferred?

Construction Robots can not take items out of requester chests (becaues the content of requesters is not part of the logistic network), but they can take from buffer chests.

[seePyou]

Another example:
Put some preconfigured buffer chests into your solar blueprint. Bam. Your logistic bots are now carrying the bulk of the solars/accus and the construction bots can concentrate on actual construction. And a logistic bot with full stack bonus carries 3 times more items than a construction bot, so they're faster too.

Isn't this accomplished just as well by a requester chest? What would the requester chest do that is worse and a buffer is preferred?

Construction Robots can not take items out of requester chests (becaues the content of requesters is not part of the logistic network), but they can take from buffer chests.

WOW!!! I had NEVER considered this as possible! This... changes a few things!!!

[Manron]

They are very usefull to prevent loops in the logistics network.

if at any point you have a requester chest output to a belt and a provider chest taking from the same belt, your bots will start moving items in an endless loop. replace the provider chest with a buffer chest and make sure the requester is not requesting from buffer chests, then there will be no loop. but still the bots can pick from the buffer and deliver stuff to where it's needed, be it a player, a construction site, or requester chests that are set to request from buffer chest.

those loop-issues were very hard to overcome before, usually requiring to built a seperate logistic network or use some combinator (black)-magic.

Please understand that I'm not disrespecting you with the following, I'm just trying to discuss it openly as I do not understand.
I dispute this solution, as not effective design. You ask too much of something that was never and should never, in my opinion work. I would never connect a requester and a provider chest with the same belt, exactly to avoid these loops. Furthermore, I see no point in this belt connecting them. I fail to see why a provider chest would be taking things off a belt that a provider chest was outputting. If you are going for "overflow", a) you don't need it, and b) you can use a storage for this. What is the exact need or scenario where such a belt connecting these two solves?

in the beginning i'm feeding my seeder factory with belts. later on i'm gradually switching to bots for the more complex crafts. i'm still running the main bus and feeding it into buffer chests close to the assemblers that need those items, so bots only run the last mile. i sometimes also got requester chests that ask for my auto-trash that are eventually connected to the bus, so there were loops.

i also had a loop issue when i was trying to feed let say yellow belts into my red belt assemblers via a requester chest that was set up to accept trashed yellow belts while maintaining a provider chest with yellow belts for expansion.
i previously solved that with combinators, but the buffer chests are so much easier to set up.

might be poor design, but i honestly dont care, it's just the temporary seeder factory that i tear down mosts parts of later anyway.

if you dont need buffer chests then dont use them. i e.g. never use lamps because i prefer night vision googles. still i dont argue about lamps being a thing for others.

but i guess you found your use case in eradicators reply.

[urza99814]

I've had problems in the past that a buffer chest might solve... Basically i had wood set to auto trash, and wanted to then use that wood to fuel my train network. So, you have the train stop request 2k wood, set your auto trash, and go cut some trees. But once you build more than one train stop you have a problem -- all the wood goes to the closest stop and the rest get starved. So you reduce the request to 100 wood at each station, but then they fill up and your trash slots don't work because there's nowhere to put it. So then you try to use requester/provider chests to create centralized storage, but instead of feeding the trains you end up with bots pulling from one end of storage just to put them back in! And soon all your bots are trapped in that loop. But if you use a buffer chest it should break that loop (AIUI... Haven't needed them in my current base as I'm not really using any bots)

Please understand that I'm not disrespecting you with the following, I'm just trying to discuss it openly as I do not understand.
There is a basic mistake in logic here, in that you have created a need of a material that is limited and is not "built". You call the lack of wood in a station "starvation" when I would call it "good use of wood". I would never build a station to run solely on wood, but I would want to build a circuit condition in the loader that would take wood if available and stop the coal/solid fuel/rocket fuel, as to use the wood I produced, when I produce it. When there was no wood, this is not "starvation", but the wood having been used as I planned, and now the trains can flow again powered by the things they were meant to be powered by.

I don't think that's really a solution. Of course you have to feed the trains with something else too, but the point is you may want to prioritize burning wood since it's not useful for much else. Which means you want wood going to all stations so it gets used faster. I don't care of they still have coal or even rocket fuel, if i have wood and the station doesn't it's still "starved" for wood in my setup. If i have ten thousand wood piled up in a single station while all my other trains burn oil, that is not a "good use of wood". If you've got a belt running to every single locomotive from one single supply point then you're fine, but that's just "fixing" the logistic network by not using it. If you want to feed the trains from more than one requester box it's going to create a loop unless you use buffer chests.

And it's not just wood either, that's just one that tends to create headaches for me... But any time you try to separate production from storage using the logistics network you're going to need buffer chests to do it.

Sure, you don't absolutely have to do that...just like you don't actually have to have steel chests or fluid tanks or any bots...just depends on how you want to design your production.

[vanatteveldt]

And it's not just wood either, that's just one that tends to create headaches for me... But any time you try to separate production from storage using the logistics network you're going to need buffer chests to do it.

I think the filtered storage chests and active storage chests are enough to do that. For production, just insert into an active provider chests and have filtered storage chests where you need them. For your wood, just have a bunch of filtered storage chests and provider chests at the stations. If you want to make sure you burn wood before coal, use separate chests and a simple condition on the coal inserter (logistic wood < X).

[Aeternus]

They are also handy for seeder factories. You know, the part of your factory where you build structures to expand.
- Connect circuit network between inserter feeding into buffer chest and said buffer chest. Inserter active only when everything <40
- Buffer chest set to demand 400 of that type of item.

When you deconstruct buildings, they go back to this seeder factory, ready to be re-used, or consumed (in case of yellow/red belts)

They are also handy for setting up defense repair/replacement supplies close to a wall/defense section to shorten construction bot travel time

Please understand that I'm not disrespecting you with the following, I'm just trying to discuss it openly as I do not understand.
Your second argument of defense repair "defense repair/replacement supplies close to a wall/defense section" is easily accomplished by requester chests. I do not understand why a requester chest for this use is worse of ill-fitted to the task.

As for the circuit network, I do not exactly understand how you have planned this. Can you elaborate? I think this is some kind of bridge and trash in one, so it sounds interesting, but I do not get it now. Can you describe it in more detail?

On the repair/supplies thing: This is something mainly for huge bases with a single logistics grid. The buffer chests can be set up on some places near wall sections to have a few replacement turrets, wall sections and repair packs. Then if something is damaged or destroyed, the construction bots in the vicinity of the repair can simply grab from the buffer chest, shortening their travel time greatly. The logistic bots can then handle replenishing the supply. Additionally, the player can be resupplied with these things if he's out and about expanding the base but had to return because you were running out of some specific structures. I believe this was the main function of these chests.

For the return-to-seeder - an example may help here.
For instance yellow belts. I have a small belt producing facility that pushes yellow belts into a buffer chest. The assembler producing red belts also takes from this chest. For belts with a stack of 100, a chest can hold 4800 items.
I connect the inserter moving yellow belts from the assembler into the buffer chest, to the buffer chest itself, so that the contents of the storage chest can be used as a condition to turn the inserter on and off. I set the condition for the inserter to "Yellow belts < 2000". Then I set the filter on the buffer chest to demand 4000 yellow belts.
The effect of this is that any excess yellow belts that get pushed into logistics storage (because of belt upgrades or deconstruction by bots), get moved back into this buffer chest, ready to be converted to red belts. If there are more then 2000 belts in the chest, the assembler is stopped from pushing more in.

This can be done with any structure maker, and can save you some resources.

As for wood - I generally set up a small incinerator for that - 2 boilers with 4 steam engines attacked to each, plus a requester chest with a 4k wood demand (and usually 100 wooden crates and early power poles too, to get rid of those). Tends to burn through that in a hurry and produces some power while at it. Not sure why you'd feed that to your trains. They run much faster on solid fuel.

[seePyou]

I've had problems in the past that a buffer chest might solve... Basically i had wood set to auto trash, and wanted to then use that wood to fuel my train network. So, you have the train stop request 2k wood, set your auto trash, and go cut some trees. But once you build more than one train stop you have a problem -- all the wood goes to the closest stop and the rest get starved. So you reduce the request to 100 wood at each station, but then they fill up and your trash slots don't work because there's nowhere to put it. So then you try to use requester/provider chests to create centralized storage, but instead of feeding the trains you end up with bots pulling from one end of storage just to put them back in! And soon all your bots are trapped in that loop. But if you use a buffer chest it should break that loop (AIUI... Haven't needed them in my current base as I'm not really using any bots)

Please understand that I'm not disrespecting you with the following, I'm just trying to discuss it openly as I do not understand.
There is a basic mistake in logic here, in that you have created a need of a material that is limited and is not "built". You call the lack of wood in a station "starvation" when I would call it "good use of wood". I would never build a station to run solely on wood, but I would want to build a circuit condition in the loader that would take wood if available and stop the coal/solid fuel/rocket fuel, as to use the wood I produced, when I produce it. When there was no wood, this is not "starvation", but the wood having been used as I planned, and now the trains can flow again powered by the things they were meant to be powered by.

I don't think that's really a solution. Of course you have to feed the trains with something else too, but the point is you may want to prioritize burning wood since it's not useful for much else. Which means you want wood going to all stations so it gets used faster. I don't care of they still have coal or even rocket fuel, if i have wood and the station doesn't it's still "starved" for wood in my setup. If i have ten thousand wood piled up in a single station while all my other trains burn oil, that is not a "good use of wood". If you've got a belt running to every single locomotive from one single supply point then you're fine, but that's just "fixing" the logistic network by not using it. If you want to feed the trains from more than one requester box it's going to create a loop unless you use buffer chests.

And it's not just wood either, that's just one that tends to create headaches for me... But any time you try to separate production from storage using the logistics network you're going to need buffer chests to do it.

Sure, you don't absolutely have to do that...just like you don't actually have to have steel chests or fluid tanks or any bots...just depends on how you want to design your production.

Let me add then, that I do the same thing to the stations as you Of course! But I do not let one station have 10.000 wook as you say, but onle request 200 for each of them, so that the "imbalance" is kept low.
However, I do see a point in this now, as your wood cannot flow UPSTREAM with my setup. If the storage chest is in the base, and that is where your wood ends up, and there are 5 stations you want to feed, each further away than the first, then I can see the Buffer chests being a good solution, instead of my old way, where it would create a huge log.bot "train" (sorry for the pun) to reach the last one.
Thank you for making me understand

[Ringkeeper]

i use buffer chests when i have to landfill a bigger lake. That takes time and i need to check on my base in between.

So i place a buffer chest ( or multiple) near the edge i will fill next and request the landfill. When i'm back , the chest will be full and the robots will immediatly fill up my inventory. I don't have to wait that they fly all the way from the unloading station to me.