Factorio Forums

Hi guys,

Relatively new to the game, have dabbled with trains, and decided to have a crack at using LTN for use in a larger base. I've watch Nilaus' video multiple times, as well as that of Diablo and the other guy that the Mod developer refers us to. I am able to get a "simple" LTN network going with the standard arithmetic setup... but I have found that I want to streamline/strengthen it a bit more by using filter inserters and a decision controller to get better controller over what's going into/out of my stations, now that I am looking to move beyond my "intermediary" base and start playing around with rockets, etc. after setting up a proper main bus.

The problem I keep running into, is that the inserters just sit there waiting for input - even if there's a full train there. I've built and rebuilt my stations after watching numerous videos/tutorials numerous times. I've also grabbed a couple of blueprints, as well as the latest tutorial map from here on the forums. Followed the configuration used in the tutorial map perfectly, as far as I could tell - same darn issue!

I am on Steam build 54889. LTN v1.14.4, and a few other mods (LTN Helper, LTN Manager (I had this issue prior to installing this - I am aware it's an Alpha), and some others not LTN-related).

In the screenshot attached, I have:

Constant combinator connected to the nearby power pole, and from there to the input light, and the chests... all via green wires.

The red wires, go from the Train Stop Output, to the Arithmetic combinator input, from the output to the LTN Train Stop and the Decider combinator input.
The decider combinator output is then wired to the inserters.

Decider config:
Red carriage != 0
Red * = input count

Arithmetic combinator config:
Standard * -1 setup

Constant Combinator config:
Request threshold <= 40k (I've tried having this at higher and lower values with no effect)
Irone ore = -50k

One thing I have noticed, is that if I mouse over the power pole between the decider and the inserters - there are no red signals, only green??? So it would seem that there's nothing coming from the decider for some reason??

Please help me find what I am sure is a stupidly simple thing that I am missing, because I don't have enough hair to spare to be pulling it out

Happy to do more screenshots or provide a copy of the save etc. if nedeed to help sort this out. I'm sure that someone more familiar with the workings of this should spot it pretty quickly, and have me kicking myself in no time... I've just not been able to spot it with the hours of mucking around and watching mass tutorials and it's doing my head in

Not sure what you are doing there. All you need is a arithmetic combinator with "each * -2 = each". If there is no carriage it makes no difference weather you enable the inserters or not for unloading.

Honestly - I've watched that many vids and looked over that many BP's, that I'm not too sure myself anymore!!

However, I did just get it going - by accidentally moving the train that had been sitting at the station full of ore the entire time because I'd turned it to manual while I did my testing, so I had something for the inserters to unload! Turns out, the logic relates to what LTN is requesting... and the load sitting at the station had timed out, so was no longer being requested...

Here's an example BP I was using for my testing, in case you're interested:

Copy blueprint

I do have a follow-up question for you - why do you say it needs to be -2, rather than -1??

bobdabuilda wrote: Wed Sep 16, 2020 9:58 pm I do have a follow-up question for you - why do you say it needs to be -2, rather than -1??

It's only relevant for stations that both request and provide.

When you have a station that both loads and unloads items and you use -1 then you will get into the situation where LTN says the train should have 200 iron plates and the train already has 198 loaded. Then the loading inserters load up another 6 plates giving you 204. That causes the math to say you need to unload 4 plates. So the unloading inserters activate and remove 6 plates bringing you back to 198 and you are cought in a loop.

By using -2 as multiplier you get 204 + (-2 * 200) = -196 and the unloading inserters won't trigger. On the other hand when there actually is something to unload you get 200 + (-2 * 0) = 200 and the unloading inserters do trigger. For unloading the item count is always 0 so the multiplier really doesn't matter. It only matters when LTN says to leave something (or load something) in the train.