Factorio Forums

While testing the new priority splitters i noticed that they cannot handle a full compressed belt. The priority splitters will start to back up the lines causing the throughput to drop.

The picture attached shows a mainbus style belt with priority splitters, and there is large gaps in the bottom belt. Compared to the normal splitters in the picture you can clearly see the difference.

I was running creative mod to illustrate the issue, i noticed it while playing without any mods.

I am having a similar issue,

when i select priority right:
- then once right belt is full
-- items go left as i think it should work.

when i select priority left:
- once the left belt is full
-- the input belt backs up even if right belt is empty
--- and very little gets through on the right
note the above screen shot
- green circuits correctly go left once right is full - right on the screen shot
-- but on the left, hardly anything goes right when priority left is selected, despite left being full.

EDIT: this is still present in 16.18

A little messing around I was doing. It looks like the issue is coming from the position of the items on the output belt to me. (please don't mind the mods, this does the exact same thing in vanilla)

Hi,

I am uncertain whether this is related or a separate bug, but I see a strange behaviour related to incoming belts into priority splitters.
When I have a splitter set to prioritize the left output belt, and I have a fully compressed left incoming belt together with a backlog on the prioritized belt, the splitter will only work (that is, properly output the overflow onto the right output belt), if either

1) there are no items of the same type anywhere on the right incoming belt
or
2) the items on the right incoming belt have reached the splitter.

This seems to also hold true for quite long distances of belt.

Unfortunately, I do not have enough time to try this with different combinations of incoming and outgoing belts, and I hope I explained it so it can be understood.

I feel like this is related to the older bug where (regular) splitters sometimes fail to handle full throughput. If that issue wasn't resolved, it almost certainly will be playing a part in this.

EDIT: Also likely duplicate of viewtopic.php?f=7&t=56924

It's not happening when the splitters are balanced. I bet the OP case has somehow messed up timing, and just bad sort of balance, which could be unfixable by devs. edit: Also would it help your case if you set input priority same as output priority?

It seams this is due to the lack of splitter input buffer (or none at all). You can see the same issue demonstrated with yellow belts connected to one side of blue splitter.
Should be solved easily by increasing splitter input buffer by at least 1 item per side.

I've noticed similar behavior on my iron bus:

gtmattz wrote:A little messing around I was doing. It looks like the issue is coming from the position of the items on the output belt to me. (please don't mind the mods, this does the exact same thing in vanilla)

I have exactly this issue. Very strange. Thanks for making a video!

I was able to reproduce several problems with the priorities, so I made automated tests of some of them and fixed the problems I could reproduce for the next release.

Since there are no savegames in this thread, I can't really confirm that it fixes all the problems, but I hope it does. (If there are more problems in the future, make a new thread please).