Allowing reading machine input, output, & trash slots separately, or read fuel without rest of contents

[macdjord]

TL;DR

When reading a machine's contents, you should be able to select between reading its inputs, its outputs, its trash, and its fuel, in any combination.

What?

Currently, when you enable 'read contents' on a machine, you get its inputs, outputs, and trash, with the option to also read inputs currently being crafted and/or fuel. There is no way to, e.g., read the machine's inputs but not its outputs, or to read just its fuel. There should be.

The UI currently looks like this:

Code: Select all

[ ]Read contents
    [ ] Include in crafting
    [ ] Include fuel

Instead, it should look like this:

Code: Select all

Read contents:
    [ ] Inputs
    [ ] In crafting
    [ ] Outputs
    [ ] Trash
    [ ] Fuel

The player can select any combination of those checkboxes, and only the selected items will be output.

Why?

Trying to set up a circuit-controlled Kovarex enrichment system so that each centrifuge only buffer exactly the 40 U235 it needs? Good luck - you can tell how much U235 is in there, but not whether its in the input slot or the output slot. How about measuring the fuel levels of a biochambre? Better hope its not doing a recipe that takes nutrients as an input or output, because there's no way to read the fuel without getting the input and output as well. Trying to build an auto-mall that needs to know if an assembler has anything in its trash slots which would block setting a new recipe? No luck there!

[eugenekay]

How about measuring the fuel levels of a biochambre? Better hope its not doing a recipe that takes nutrients as an input or output, because there's no way to read the fuel without getting the input and output as well.

You can Toggle Filter (Middle Click) the Biochamber Fuel slot to set a Filter. Choose a Quality level different from that of the Recipe.

08-27-2026, 09-32-14.png (109.58 KiB) Viewed 1205 times

Good Luck!

[macdjord]

How about measuring the fuel levels of a biochambre? Better hope its not doing a recipe that takes nutrients as an input or output, because there's no way to read the fuel without getting the input and output as well.

You can Toggle Filter (Middle Click) the Biochamber Fuel slot to set a Filter. Choose a Quality level different from that of the Recipe.
08-27-2026, 09-32-14.png

Good Luck!

Which has nothing to do with reading the amount of fuel in the machine.

[Bilka]

You can already read fuel separately in 2.1.

[Alfonse215]

You can already read fuel separately in 2.1.

You can't read the fuel without reading the inputs and outputs too. If an ingredient and fuel are the same item, you can't tell them apart.

[Alfonse215]

How about measuring the fuel levels of a biochambre? Better hope its not doing a recipe that takes nutrients as an input or output, because there's no way to read the fuel without getting the input and output as well.

You can Toggle Filter (Middle Click) the Biochamber Fuel slot to set a Filter. Choose a Quality level different from that of the Recipe.
08-27-2026, 09-32-14.png

Good Luck!

Which has nothing to do with reading the amount of fuel in the machine.

I think the point is that the main reason to care about that circumstance is if you're using a recipe that has nutrients as an ingredient. If you're making high-quality fish, you don't want to burn precious high-quality nutrients making them. By filtering the fuel slot to base-quality only, you don't need to read the fuel to see whether it's empty or not; base quality nutrients go in the fuel automatically since they cannot go into the higher-quality input slot.

[Bilka]

You can't read the fuel without reading the inputs and outputs too. If an ingredient and fuel are the same item, you can't tell them apart.

You can already read fuel separately in 2.1.

Screenshot_20260828_075528.png (917.67 KiB) Viewed 1040 times

[Shirasik]

You can't read the fuel without reading the inputs and outputs too. If an ingredient and fuel are the same item, you can't tell them apart.

You can already read fuel separately in 2.1.


Screenshot_20260828_075528.png

Let's say I need to read nutrients as fuel and nutrients as recipe input (e.g. in egg breeding recipe) separately. How do I do that?

[mmmPI]

Let's say I need to read nutrients as fuel and nutrients as recipe input (e.g. in egg breeding recipe) separately. How do I do that?

Judging from the MANY topics about this particular question : you can't do that.

At first you couldn't "read fuel" at all , but it was requested :

viewtopic.php?t=118631
viewtopic.php?t=120689

But still in some cases it wasn't enough, so there was the possibility to add filter on the fuel slot to cover cases when the default insertion priority would not be safe :

viewtopic.php?t=122818
viewtopic.php?t=126252
viewtopic.php?p=671950
viewtopic.php?t=129775

This is just about the particular nutrient and biochamber part, the overall suggestion to modify the circuits network like discussed in the OP was discussed in other topic less specific than this particular nutrient in biochamber one plenty times too.

It appears to me that the direction the game went is to provide different means to answer what problems could have been also solved by different methods, such as the one suggested which is more granular than current implementation and thus would allow to solve a larger/extended set of problems. However, it also appears that the game was designed so that the problem a player would face could be adressed with the tools it provides. (e.g you can do egg breeding, auto-mall, and precisely-buffered kovarex enrichment just fine currently imo). Which i feel unsurprisingly players would point out when it comes to problems solvable in a different ways or arising from what could appear as a unvoluntary self-imposed challenge. "why would you need that when we can solve the problem without ?"

[eugenekay]

How about measuring the fuel levels of a biochambre? Better hope its not doing a recipe that takes nutrients as an input or output, because there's no way to read the fuel without getting the input and output as well.

You can Toggle Filter (Middle Click) the Biochamber Fuel slot to set a Filter. Choose a Quality level different from that of the Recipe.
08-27-2026, 09-32-14.png

Good Luck!

Which has nothing to do with reading the amount of fuel in the machine.

I think the point is that the main reason to care about that circumstance is if you're using a recipe that has nutrients as an ingredient. If you're making high-quality fish, you don't want to burn precious high-quality nutrients making them. By filtering the fuel slot to base-quality only, you don't need to read the fuel to see whether it's empty or not; base quality nutrients go in the fuel automatically since they cannot go into the higher-quality input slot.

Let's say I need to read nutrients as fuel and nutrients as recipe input (e.g. in egg breeding recipe) separately. How do I do that?

If the Ingredients are Normal Quality and the Fuel is Uncommon quality then you will get two different Signals while using “Read Contents”. It is not Perfect, but it Works as-is.

[Alfonse215]

You can't read the fuel without reading the inputs and outputs too. If an ingredient and fuel are the same item, you can't tell them apart.

You can already read fuel separately in 2.1.


Screenshot_20260828_075528.png

Let's say I need to read nutrients as fuel and nutrients as recipe input (e.g. in egg breeding recipe) separately. How do I do that?

The problem there is that this would require putting those values on separate wires. The devs had the opportunity to have each individual input/output be assigned to different wires, but they didn't. It's just "all the inputs" and "all the outputs". So they're probably not going to do that now for this very small edge case.

It's also not clear when you would "need" to be able to do this. You said that you'd be doing it for egg making, but... what are you going to use that information to do in such a setup?

Previously this would have been useful for quality egg making, so that quality nutrients wouldn't be used for fuel. But with fuel filtering, that's no longer necessary.

[Shirasik]

Previously this would have been useful for quality egg making, so that quality nutrients wouldn't be used for fuel. But with fuel filtering, that's no longer necessary.

I experimenting with different module setups because at some point I found out some efficiency capped setups are quite UPS-friendly due to very low pollution generation. While egg breeding don't really need efficiency in that sense I want to keep experimenting anyway. The problem is efficiency-capped biochambers consume nutrients very, very, very slow so bulk-inserted nutrients manages to rot before auto-insertion comes up with next batch. Obvious solution: override stack size of nutrient-loading inserter to 1 and hook it to biochamber with "read fuel" checked. There comes two problems:
1) in general case I need to filter out fuel nutrient signal before letting "read contents" signals being pushed further. While technically solvable through arithmetic it adds 2-tick delay which desynchronises signal input forcing me to add 2-tick delay everywhere else around. Along with 1 tick for biochamber to push values to network, 1 tick for inserters to digest signals from network and at least 1 tick for control logic it reaches a 5-tick breakpoint of 180-degree rotation of legendary inserters. That hurts strictly synchronised setups sometimes thus limits me to "low-frequency" setups.
2) in case of egg breeding I need not just to read input and fuel separately. I also need to load input and fuel separately: one inserter puts fuel nutrients with stack size of 1 and other inserters puts input nutrients in full bulks.

[Alfonse215]

I experimenting with different module setups because at some point I found out some efficiency capped setups are quite UPS-friendly due to very low pollution generation.

While pollution spread does consume UPS, I haven't heard anything about pollution generation itself being a UPS issue. Do you have any sources for this? Does it apply to planets where pollution isn't tracked, or on Gleba where "pollution" comes from other sources?

1) in general case I need to filter out fuel nutrient signal before letting "read contents" signals being pushed further.

... why? What are you reading the contents for that having an extra nutrient signal would be a problem?

Furthermore, without the ability to send the inputs and fuel to different wires, what you're asking for wouldn't help.

2) in case of egg breeding I need not just to read input and fuel separately. I also need to load input and fuel separately: one inserter puts fuel nutrients with stack size of 1 and other inserters puts input nutrients in full bulks.

They're not going to add the ability to direct inserters to different kinds of slots. That's modding territory.

[mmmPI]

I experimenting with different module setups because at some point I found out some efficiency capped setups are quite UPS-friendly due to very low pollution generation.

Biochambers do not produce pollution but actually REMOVES it during their normal activity on Nauvis, when you cap their efficency with module, you also reduce this effect which is proportionnal to their energy consumption. If you want to keep low pollution generation, it appear counter productive to use efficency module.

If you want to "keep some biochamber running doing egg breeding" on Gleba for low nutrient consumption, it is possible to do so without having the nutrient fuel turn into spoilage, even with a biochamber whose efficency is capped by module, but you need to provide "fresh enough nutrient" , here are 2 setups to illustrate :

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

Copy blueprint

"Read content" and "read fuel" are used, inserter's stack size is limited to 5 for the nutrient, and only active when nutrient is under 40. The small setup maintain a good enough nutrient freshness that it doesn't produce spoilage from the fuel rotting even if it is consumed as slow as the game can make it. For the larger one on the other hand, the loop is too long and eventually the average freshness of nutrient's input becomes low enough that some of the nutrient fuel turns into spoilage.

Obvious solution: override stack size of nutrient-loading inserter to 1 and hook it to biochamber with "read fuel" checked. There comes two problems:

With stacksize 1 the nutrient inserter is to slow to maintain the biochamber fully running, with size 5 it's fine, and it allows to never have more than "9" nutrients loaded in the fuel slot at the same time, and you need 30 for the receipe so the total nutrient count in the biochamber shouldn't exceed 39, or 40 to round it up. And it doesn't spoil at all.

[Shirasik]

While pollution spread does consume UPS, I haven't heard anything about pollution generation itself being a UPS issue. Do you have any sources for this?

https://www.youtube.com/@abucnasty
Look up for videos with "pollution" word in the name.
Just the size of pollution cloud is already enough to hit UPS significantly. Two general conclusions:
1) it is better for UPS to keep pollution cloud small;
2) most UPS-friendly way to consume pollution is tree farms that are working through pollution damaging trees.

Also just from in-game knowledge you may know at least three things:
1) pollution spread is done through pollution level comparison of neighbouring chunks thus more pollution means more chunks are "active";
2) if pollution hits edge of generated chunks the game generates more chunks thus allowing pollution to spread and activate more chunks and generates more biters;
3) if pollution level in chunk hits certain number then game begin to damage trees in the chunk thus making every affected tree an active entity that needs to be calculated over individually.

Do you follow? High pollution generation leads to high per-chunk pollution which activates trees as calculation-demanding entities. Nevertheless you need many renewable trees as they are the most efficient way to consume pollution. Efficiency-capped setups allows for never-renewed tree farms thus having zero active trees and zero active agri towers while keeping pollution cloud being contained strictly thus never activating biters and never generating new chunks.

... why? What are you reading the contents for that having an extra nutrient signal would be a problem?

As I said while technically solvable it limits me to "low-frequency" control logic. I want to design controls that keeps state of controlled unit synchronised within 5 ticks delay of legendary inserters swing back to source (so sync is considered virtually instant) but I can't because UI doesn't allow me that.

Biochambers do not produce pollution but actually REMOVES it during their normal activity on Nauvis, when you cap their efficency with module, you also reduce this effect which is proportionnal to their energy consumption. If you want to keep low pollution generation, it appear counter productive to use efficency module.

Read again please:

While egg breeding don't really need efficiency in that sense I want to keep experimenting anyway.

inserter's stack size is limited to 5 for the nutrient

Let's see. Efficiency-capped biochamber consumes 100kW of yummy value and nutrients provide 2MJ of that. So single nutrient item is enough to keep biochamber working for 20 seconds. Auto insertion triggers when fuel input cache of biochamber has fewer nutrient items than 5. With one already taken as active fuel it's 5. Plus your inserter will add 5 so it's 10 in total. In order to never rot all that nutrients must be consumed in 200 seconds. With 300 seconds lifespan of Q1 nutrients it limits me to at least 67% fresh nutrients when they are picked from source. Well that is achievable due to high nutrient consumption of egg breeding recipe but it raises a requirement of freshness e.g. I can't use 66% fresh bioflux. Actually along with nutrients on belts travel time and a bit of time them sitting at the end of belts I need like >90% fresh bioflux as a strict requirement. How to read freshness and push its value into logic network?

[mmmPI]

Biochambers do not produce pollution but actually REMOVES it during their normal activity on Nauvis, when you cap their efficency with module, you also reduce this effect which is proportionnal to their energy consumption. If you want to keep low pollution generation, it appear counter productive to use efficency module.

Read again please:

While egg breeding don't really need efficiency in that sense I want to keep experimenting anyway.

I did read several time before making the blueprints, it's because i was unsure of what you meant that i wrote what i thought of a clarification/ ask for one.
I understand this is part of an experiment, my opinion is that the suggestion would allow "more" experiment, i may have been very unclear in my wording, my feeling is that it would be nice on its own, because a more versatile tool is "good", but also that currently in the game the tools given allows to solve the challenges the games offer. Typically there are some mods that add complexity that would benefit from it, and it would allow modders to design more complex challenges if players have more versatile tool to begin with. That's what motivate my interest in the suggestion.

I thought interesting the case of nutrient spoiling in the fuel slot of efficency capped bio chambers because it's not directly what the filter in the fuel slot was meant to adress i feel. And it wasn't mentionned with such angle in the many listed thread previously, so i went for an experiment of my own

inserter's stack size is limited to 5 for the nutrient

Let's see. Efficiency-capped biochamber consumes 100kW of yummy value and nutrients provide 2MJ of that. So single nutrient item is enough to keep biochamber working for 20 seconds. Auto insertion triggers when fuel input cache of biochamber has fewer nutrient items than 5. With one already taken as active fuel it's 5. Plus your inserter will add 5 so it's 10 in total. In order to never rot all that nutrients must be consumed in 200 seconds. With 300 seconds lifespan of Q1 nutrients it limits me to at least 67% fresh nutrients when they are picked from source. Well that is achievable due to high nutrient consumption of egg breeding recipe but it raises a requirement of freshness e.g. I can't use 66% fresh bioflux. Actually along with nutrients on belts travel time and a bit of time them sitting at the end of belts I need like >90% fresh bioflux as a strict requirement. How to read freshness and push its value into logic network?

I would say it's not strictly 10 but rather 9 total for the circuits, i only added 1 for safety, because the inserter feeding nutrient activate when the quantity of fuel becomes "4", it goes 6 6 6 6 5 5 5 5 4 9 9 9 8 8 8 8 , where the amount of time when it's 4 or 9 combined roughly represent the duration of 1 nutrient being consumed (sorry for the nitpick), the "raising freshness requirement" as a consequence is what i wanted to illustrate after experimenting. This was set up after observation not precise math for duration. I made the small setup first then i progressively made longer the belt loop so that the average freshness of the nutrient would lower and it would cause the setup to start failing. I think a worse case scenario is the fish breeding receipe because instead of 30 nutrient it requires 100, which makes the stack size of 5 insufficent to maintain the biochamber fully running. If you increase the stacksize, you then increase the maximum of nutrient that can be in the fuel slot at any time from 9 to 10 to 11 to 12 and so on which mechanically raises the freshness requirement to harder level, similarly using 2 inserters can cause them to refill the fuel slot at the same time also raising the freshness requirement to potentially unsustainable level.

And one can't read the freshness in the circuit, still the problem CAN be managed differently, having a few nutrient spoiling in that slot occasionnaly can be made into a "small" % of waste without escalation into full disruption, you don't strictly need to guarantee no spoilage would ever form there, you can also increase the quality of the nutrient you use as fuel, to have them last longer for the same % of freshness and make use of the filtered slot this way x)

The most realistic would be to shorten the delay in the whole factory between production and consumption, and this is clearly a case that's putting to stress the current system where the suggestion could be used to give finer control to the player, by manipulating dynamically the stack size around the "fuel" read separately from the "nutrient input". But one doesn't 'have' to put themselves into such situation where it would be problematic to have "some" spoilage occasionnaly forming there and i see it as part of the game to deal with the consequence. (imo) I would welcome the suggestion anyway , but at the same time i don't think it's a "need" rather it's a desire for some extra.

[macdjord]

You can't read the fuel without reading the inputs and outputs too. If an ingredient and fuel are the same item, you can't tell them apart.

You can already read fuel separately in 2.1.


Screenshot_20260828_075528.png

That is, in fact, exactly what I wanted and suggested with respect to fuel! Now we just need separate checkboxes for reading inputs, outputs, and trash.

[mmmPI]

That is, in fact, exactly what I wanted and suggested with respect to fuel! Now we just need separate checkboxes for reading inputs, outputs, and trash.

It's actually not needed for any of the use case you mentionned though and there would be no way to read 3 distinct value from only from 2 wires colors , how do you expect a kovarex enrichment to be different if the suggestion is implemented ? Or if one measure the "input" and the "fuel" on 2 different wire, how are you going to read the trash slot on top of that ?

Your suggestion appears to request something that wouldn't solve the problem the way you explained it as if you have a biochamber that switch between 2 receipe, one having nutrient as input, then you NEED to read the nutrient in the input slot, in the fuel slot, and in the trash slot but the suggestion would not allow.

Having the possibility to select the wire color for each tickbox individually would be nice, but the arguments for the trashslot and the "need" for a different system are not convincing me.

[Shirasik]

I think a worse case scenario is the fish breeding receipe because instead of 30 nutrient it requires 100, which makes the stack size of 5 insufficent to maintain the biochamber fully running.

Nutrient economy on Nauvis is very different from nutrient economy on Gleba. On Gleba your best nutrient source is bioflux->nutrients recipe which gives 20 nutrients per 1 bioflux tops (40 base +50% biochamber boost +100% from 4x T3Q5 productivity modules = 100 nutrients made from 5 bioflux) and inherits rot progress from bioflux. On Nauvis your best nutrient source is biteregg->nutrients recipe which gives 50 nutrients per 0.06 bioflux tops (captive spawner eats ~0.06 bioflux per second, Q5 captive spawner produces 1.25 eggs/second; recipe gives 20 nutrients per egg, 4x T3Q5 prod modules gives another 20 per egg; 40 nutrients/1egg * 1.25eggs / 0.06 bioflux = 50 nutrients / 0.06 bioflux)(so literally up to 50/0.06 ~ 833 nutrients per 1 bioflux (!!!)) PLUS captive spawner don't inherit rot progress of bioflux and keeps eggs fresh until they are extracted (i.e. needed). Such ratio and freshness conditions makes all biochamber recipes available on Nauvis very viable and economical although slightly specific in management. (Also you might get an idea of continuous export of biter eggs to Gleba.)

As for fish breeding. Recipe requires 100 nutrients per 6 seconds-long cycle. Assuming you using Q5 biochamber with base crafting speed of 5 the recipe will require at least 100 nutrients per 1.2 seconds or 100/1.2 = 83.3 nutrients per second (so stacked red or faster belt will manage). Or 100 / (1.2 * 60) = 1.3(8) ~ 1.4 nutrients per tick. Biochamber is a 3x3 structure so its perimeter is 12 tiles long. Let's reserve 1 tile for output (for fish), 1 for input (for fish) and 1 tile for spoilage removal. We still have 9 input lines. Assuming you using fast+ Q5 inserters we need 5 ticks to swing inserter forth and another 5 to swing back, 1 tick to drop nutrients into biochamber and some ticks to grab items from belt what is a variable so let us be conservative and consider this extra as another 9 ticks. With stack size of 4 and assumed 20-tick long work sequence of fast Q5 inserter we have 4 nutrients loaded per 20 ticks = 0.2 nutrients per tick. 1.4 / 0.2 = 7. So I believe 7 fast Q5 inserters will manage. Plus 1 more inserter to manage fuel insertion demand. And still we have 1 unused perimeter tile left.

The most realistic would be to shorten the delay in the whole factory between production and consumption, and this is clearly a case that's putting to stress the current system where the suggestion could be used to give finer control to the player, by manipulating dynamically the stack size around the "fuel" read separately from the "nutrient input". But one doesn't 'have' to put themselves into such situation where it would be problematic to have "some" spoilage occasionnaly forming there and i see it as part of the game to deal with the consequence. (imo) I would welcome the suggestion anyway , but at the same time i don't think it's a "need" rather it's a desire for some extra.

For now the most viable option is to use fuel of different (compared to fuel-mightbe item in recipe input) quality as this eliminates the very possibility to mix recipe input and fuel. But that is a workaround which requires to track fuel in order to permit input load so input inserters will not push anything into fuel slot and always to have proper item in fuel input slot with a quantity of at least 2.

[mmmPI]

With stack size of 4 and assumed 20-tick long work sequence of fast Q5 inserter we have 4 nutrients loaded per 20 ticks = 0.2 nutrients per tick. 1.4 / 0.2 = 7. So I believe 7 fast Q5 inserters will manage. Plus 1 more inserter to manage fuel insertion demand. And still we have 1 unused perimeter tile left.

Just need to make it happen then

I didn't check the details of the math, but the general idea to illustrate the worse case scenario i think i understand. If you were to use 7 fast Q5 inserter for the biochamber, you would probably want to avoid the case where they "all" refuel the nutrient at the same time, as that would necessarily cause some of it to spoil before the biochamber consumes it, but with only 2 groups, the maximum nutrient in the fuel slot would be 20 ( with the stack size of 4 and 4/3 for the grouping plus the residual nutrients). This is still manageable with the "perfect" mindset that no spoilage should ever form there. But even if , the spoilage could still be dealt with therefore reading the fuel and the nutrient as input on different wire doesn't appear strictly necessary given the receipes and the general balance of the game.

The math gets tricky because although you may have more nutrient in the fuel slot that could turn into spoilage, those being added are also "fresher" on average than those standing inside the biochambers and you'd be adding more of them at the same time so in order to properly math and model the dynamic of the constantly averaging freshness in the fuel slot of the biochamber, i feel you would need to account for the pseudo-random variations that would occur , and those more periodic and predictible when the factory restart/stop production or make assumptions that there is no loops and all nutrients are either consumed by said biochambers or pushed further in the factory for "less critical" receipe. There are already several architecture possibles.

For now the most viable option is to use fuel of different (compared to fuel-mightbe item in recipe input) quality as this eliminates the very possibility to mix recipe input and fuel. But that is a workaround which requires to track fuel in order to permit input load so input inserters will not push anything into fuel slot and always to have proper item in fuel input slot with a quantity of at least 2.

You could use fuel of a different quality, that's a different method, maybe a work-around the first one that would be utilizing circuits and/or stacksize to make it work, depending on your method to aquire this quality nutrient to use as fuel however you may end up causing more waste there than you try to prevent with the whole controlling the nutrient precisely. It's a trade-off which depens on the very build players make i feel.