Combinator multiplexing help

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credomane
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Combinator multiplexing help

Post by credomane »

I'm sure someone has made this before. I started working on this a long long time ago probably before even factorio 1.0 but never finished it due to issues. Then when I saw a multi-channel for radar's for 2.1 suggestion elsewhere on this forum it made me want to finish this idea.

So I got started on it again this evening and greatly simplified it from the old version. I modified it from the original intention of running over my "rail" network (rail bps had power and circuit wires included) to running over radars. Then with the 2.0 features the number of combinators used is one-fifth of what it was before. However the same problem I had before is still present due to the 1-tick delay of the combinators. There is flickering that I can't figure out how to get rid of.

The writers update after 1 tick after the controller changes the ID (I signal), as expected, however the readers update fully after 3 ticks. The 1st tick after an ID change has the readers showing the circuit data from the previous ID (because the writers got the ID change at the same time and old signals are still present), the 2nd tick has the readers showing nothing (because the new ID signals just now hit the readers) and the 3rd tick has the correct data being output from the reader. At least that is my understanding after stepping tick by tick using /editor mode.

As I said before I'm sure someone has already made this and it works. I'll by all means just use that assuming someone is willing to share it with me. No need to reinvent the wheel after all.

BP with a setup containing 3 sets of readers and writers.


BP Book of the current version of my controller, reader, writer



[edit]
Changes the code blocks to bp blocks. I missed that in my sleepiness last night.
Last edited by credomane on Thu Apr 24, 2025 2:51 pm, edited 1 time in total.
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mmmPI
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Re: Combinator multiplexing help

Post by mmmPI »

Hey, seeing your post made me update 2 versions of those thing made with the modded anticipation of current radar. They do work fine now, but are not based upon your design :

Here is one 'simple' version that uses a modded push button to call a new outpost : 111877

This one only has "emiter" which are called "outpost" , and a single "receiver" that also act as controller.

And another one more advanced that uses a clock , no mod required , is more similar to your design but i think holds a few differences :
112723

This one is composed of a "controller" that i called clock, "outpost" which are emitter, and 1 area that draw graph, which would be the receiver, hence why i see it as similar.

It isn't using any of the new 2.0 fancy feature with combinators and parameter, only radars and is already pretty minimalist if not considering the extra combinators for unecessary things, like RNG generator in each outpost to make numbers for the large graph display, hopefully that doesn't make it too much of a mess. The core logic is quite minimalistic and close to yours.

This is a blueprint book that features the 3 parts in a usable way without looking the save games, but it's recommended ( and to use the editor to time tick by tick ) to understand what differs between outpost, to use as parameter and how back-propagation can be avoided.



I don't know if the explanations are enough, and would gladly attempt to go more in details if there are some parts that are unclear, not working for you, or if you are interested in those designs :)
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Tertius
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Re: Combinator multiplexing help

Post by Tertius »

credomane wrote: Thu Apr 24, 2025 5:36 am There is flickering that I can't figure out how to get rid of.
Sorry to ask this dumb question, but what exactly do you mean with "flickering"? Is it your clock (signal I) isn't in sync to the responses, and the values are only stable after the 3 tick delay?

There is a trivial solution. And it allows the whole thing running with a clock of 1 tick, not with 3 ticks interval.

The original clock is I on the red wire distributed with the radars. Use this signal on the writers only. Change the writers to send their I along with the signals they're supposed to send when their I matches. On green wire. This I on green is synchronized with the signals+values, so use this I on the readers to set the memory cell. Don't read I from red wire.
You will share the index signal with the remote signals and lose the ability to use I as signal+value, but that's probably a tiny loss.
The clock generator for the red I can be trivial: Just a counter from 1..max. It contains a separate constant combinator to count from 1..max, not 0..max, since 0 isn't a valid index.
I also reduced the readers to have just a memory cell of 2 combinators, however they output their signal on the opposite color (red) - if you don't want this, you can add a 3rd combinator to switch the wire.

The display panels on the right are there to prove I and signals are synchronized.
04-24-2025, 15-56-25.png
04-24-2025, 15-56-25.png (335.23 KiB) Viewed 188 times



You can also add this 3rd combinator to delay the I signal from red wire by 1 tick and use this as SET condition for the memory cell. Use an arithmetic combinator with I=I+0. This is more similar to your original blueprint, since it doesn't change the writers and don't transmit the I back. The I on red is always 1 tick ahead of the signals coming back from the writers, so they are synchronized again, if you add a 1 tick delay to the red I.
You don't need to react to a changed I, which introduces 2 additional ticks latency - you know the I is always 1 tick ahead, so you can use this fact.

This is a changed blueprint with just the readers modified and the simplified clock generator. It uses one combinator more than in the screenshot, but has again the I not polluting the output on the readers and have its signal on green again.

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credomane
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Re: Combinator multiplexing help

Post by credomane »

Tertius wrote: Thu Apr 24, 2025 1:51 pm Sorry to ask this dumb question, but what exactly do you mean with "flickering"? Is it your clock (signal I) isn't in sync to the responses, and the values are only stable after the 3 tick delay?
I was really bad at trying to explain what is going on there. Yes, the output signals are out of sync leading to incorrect signals for a few ticks before it stabilizes and has the right signals. I haven't managed to figure out how to fix it and it is driving me mad. You can really see it if you slow the game speed down or go tick by tick with the /editor.

I'll give it another go and try to explain it properly.
If you watch the signals on the pole on the readers (except for I==1 because technically I==0 is a valid ID too but I don't use it.) They will all flicker when the I signal changes. So for this bad explanation let's say you are looking at the pole for the reader of I==2. When the I switches from I=1 to I=2 the pole will be showing the correct data. At tick+1 it will be showing the wrong data as it will be the signals from I==1 but we are looking at I==2's pole! Then at tick+2 the I==2 pole will be blank. Finally at tick+3 the I==2 output pole will finally be showing the right signals for I==2. Really hope that explanation is right. I'm running it from memory after banging my head on the desk for 3 hours trying to fix it last night plus forgotten amounts of hours spent stuck at this exact place years ago. If you swap the signals around so it is doing colored lamps instead (dunno why i wasn't already doing that in my testing) it should make the issue I'm trying to describe super obvious.

I know whatever is wrong with my design it is on the reader side. I just found this multiplexer BP on factorio prints and looking at the screenshot it does what I want and as an added bonus it manages to do everything over a single wire too. If that BP works without flickering/cross-talk I can do some simple wire color swapping and have two multiplexers running, one each for red and green. Doubt I'll ever need that much multiplexing though. I'm still going to continue to play with my design as just using someone else's design won't teach me anything.

I'll definitely take a look at the BP you two posted tonight.
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credomane
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Re: Combinator multiplexing help

Post by credomane »

Well I figured out how the other BP worked pretty quick and it was really obvious what I was doing wrong. I really should have seen it sooner. The readers/demodulators are purposely offset by ONE id from the writers/modulators so as to account for the 1-tick propagation delay. *facepalm* I was already thinking about how to do that but every attempt got really really complicated but I persevered and eventually got it working.

Soon as I got that working in my design I was quickly able to make everything else work without issues (no more flickering!) and actually found it worked better having each channel id broadcast for a single tick (same as how it was done in that other bp). I thought for sure I was gonna need 2 minimum. I then started simplifying it (reducing number of combinators needed) and pretty much ended up duplicating the other BP once I switched to using negative numbers for the controller/clock's channel ID signal output. Was surprised how much that alone reduced complexity/combinator count. This I think is my final design:


My controller is placed once per surface and by default keeps a clock signal running on both red and green wires. You can just disconnect red or green from the radar if you want to use that color for something else. I then have a modulation/demodulation pair for both red and green wires. Just use the arithmetic combinator for input/output of your signals and off you go!

Here is a screen shot of the working system and showing that red/green are independent of each other. Top center is the controller/clock. The rows are channels 1-4. column 1 is the modulators (row 1 and 2 are green and row 3 and 4 are red). Column 2 is green demodulators and column 3 is red demodulators.
04-24-2025, 23-27-03.png
04-24-2025, 23-27-03.png (4.3 MiB) Viewed 97 times
As you can see everything is working perfectly. Here is the bp of the screenshot setup:
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mmmPI
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Re: Combinator multiplexing help

Post by mmmPI »

display pannels at each outpost is a nice touch i'm going to borrow :)
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