When there is an extreme shortage of a resource, does SSSP ration the resource across all of the sinks, equally? Or does it favour one? Or choose them at random?

I have built a factory that currently has a shortage of copper wire (obviously I'm going to fix that!). But it seems to be sending the available supplies all to the same sink station(s), ignoring the others. It also sits idle for ages, with plenty of available copper wire in its storage, presumably until the "favoured" sinks require more.

Any ideas what's wrong? Has it lost track of some stations, perhaps?

Here's a save of the game, with the avatar at one sink that is apparently being ignored:

https://drive.google.com/file/d/1hSu81zTb3oxvfL200YpMFJZPS3q7gq8S/view?usp=sharing

And here's a screenshot showing the position of the source of copper wire that I would expect to be supplying it at some point:

https://drive.google.com/file/d/1MTpc3_DFAv9Ehem9-uvgsoUG4n6mvhhv/view?usp=sharing

PS.

I've tried changing the latency value but that doesn't seem to do anything to help. Maybe I've broken something?

Thanks.

So, things are in fact working as intended: The pull station that the player is at isn't actually below the threshold for getting a delivery yet.

Basically, there are actually two different thresholds for pull stations: the sink threshold, and the pull threshold. This station has met its sink threshold (8000 items), but not its pull threshold (8400) items. This means it can receive items from push stations, but not from source stations.

The reason this is a problem is because of the way you are unloading the station. Items in the chest at the top are not able to get to the belt at the bottom. You need another splitter to mix the two output belts.

I didn't realise that there were two thresholds. Where is the other threshold shown? Everything I looked at said 8000 :)

re: your comment about unloading the station - I understand the reasons for the empty assemblers in the middle and that is a temporary thing (I'm in the middle of a big change to the whole factory, as I move to Express + 6x6 containers).

Would it be hard to add a status string to the train stop display, describing why nothing is apparently happening, e.g. "a train is collecting items" or "need room for more, as the source wants to send me 8400"?

The "deliveries" window is nice, but it doesn't tell you why there aren't any trains coming.

The thresholds aren't shown, but they are quite simple. The threshold for deliveries from push stations is just delivery size (8000). The threshold for deliveries from source stations is half way between delivery size and the maximum (storage needed * stack size = 8800). The reason there are two thresholds is for complex setups where you are dealing with byproducts that really need to get used before items from normal providers. Generally, you don't really need to know about all of this, except in this case where it is a bit confusing that deliveries aren't happening.

I should mention though that even if there were only one threshold, that unloading setup would still lock up eventually, once the chest up the top had at least 800 items in it. Then the deficit would drop below 8000.

As for showing more info about why deliveries aren't happening, you are right, the mod should definitely give some kind of explanation. But I do have to try and strike a balance between showing too much useless info and it being overwhelming, and not showing enough. I'll see what I can do anyway :)

Thanks. I do understand the problem about overwhelming the user interface. Perhaps repurpose the "current deficit" value to be the maximum value of the threshold required? Keep the label title of "current deficit", but change the value that it displays.

"From the outside", I want to be able to ensure that my storage is always big enough and that it will always try to deliver what I'm asking for, i.e. that value "x" (delivery size) is less than value "y" (current deficit). I don't actually need to know how you are calculating that value "y". So, it won't matter to me that 'y' is not a simple single parameter, but is actually the maximum of two hidden ones.

How does that sound?

PS,

Re: your comment about the top chest locking up, you are correct. As I said in an earlier response, this was a temporary hack I use until until I get access to a single 6x6 container. I tend to build up a lot of "technical debt" at the start of a new game, which eventually gets cleaned up. :)