[kovarex] [0.16.22] Belt back pressure inconsistency

This subforum contains all the issues which we already resolved.
Post Reply
quyxkh
Smart Inserter
Smart Inserter
Posts: 1027
Joined: Sun May 08, 2016 9:01 am
Contact:

[kovarex] [0.16.22] Belt back pressure inconsistency

Post by quyxkh »

Watch the inserters, you can see that one lane's getting much more backpressure transmitted than its belt partner even though the items are moving at the same rate (and I think there "should" be no backpressure at all, since these are priority splitters with clear output paths, but I wouldn't call that a bug).

The effect shows up more subtly in the #4 inserter, but the traffic there is clearly identical in both lanes.


blueprint

Mimos
Long Handed Inserter
Long Handed Inserter
Posts: 73
Joined: Mon Nov 07, 2016 5:15 pm
Contact:

Re: [0.16.22]backpressure glitch (?)

Post by Mimos »

It took me al while to understand what you mean because at first I just looked at what the splitters do.

Especially when watching insterter #8 and the splitter above it I always see a free output on the splitter but still it somehow seems to decide to not accept input for a short time. This ist what you meant, right?

Another thing I noticed when watching Inserters #5 and #6: somehow the first steel of each "grab" of inserter #5 seems to jump ahead. (The alternative was the rest of the Items being blocked for a short time but that is impossible because then both inserters wouldn't be synchronous.)

kovarex
Factorio Staff
Factorio Staff
Posts: 8078
Joined: Wed Feb 06, 2013 12:00 am
Contact:

Re: [0.16.22]backpressure glitch (?)

Post by kovarex »

I don't understand this report, sorry. What is backpressure on a belt?

quyxkh
Smart Inserter
Smart Inserter
Posts: 1027
Joined: Sun May 08, 2016 9:01 am
Contact:

Re: [0.16.22]backpressure glitch (?)

Post by quyxkh »

Sorry if I invented a term, I mean what happens when exit lanes are at capacity so the input lane traffic backs up. Watch the #6 inserter gradually get out of step with the one loading the other lane.

I think now that this is a not-a-bug, an accident of timing that I missed noticing, I can see that the lane merge makes the priority-merge splitters take different number of items per lane,

seePyou
Long Handed Inserter
Long Handed Inserter
Posts: 98
Joined: Mon Apr 03, 2017 3:17 pm
Contact:

Re: [0.16.22]backpressure glitch (?)

Post by seePyou »

But there is nothing blocking inserters 4 and 8 and they are always free to insert steel on the belt! I do not understand why these inserters are going off sync with their "brothers". Can anyone explain?

Aeternus
Filter Inserter
Filter Inserter
Posts: 835
Joined: Wed Mar 29, 2017 2:10 am
Contact:

Re: [0.16.22]backpressure glitch (?)

Post by Aeternus »

There is something blocking them actually. The splitter they feed has one end of it's output blocked.

seePyou
Long Handed Inserter
Long Handed Inserter
Posts: 98
Joined: Mon Apr 03, 2017 3:17 pm
Contact:

Re: [0.16.22]backpressure glitch (?)

Post by seePyou »

So? If one end of a splitter is not blocked, it should not block the input at all! I was watching the animation closely, and the right side (as we see it) of the belt input and output of the right side of the splitter is always free. As such, inserters 4 and 8 should never be blocked? Maybe that is a defect in itself?

Iccor56
Long Handed Inserter
Long Handed Inserter
Posts: 65
Joined: Mon Dec 25, 2017 12:29 am
Contact:

Re: [16.22] Belt back pressure inconsistency

Post by Iccor56 »

remaking this gif with 'show info' on would be helpful

Zaflis
Filter Inserter
Filter Inserter
Posts: 414
Joined: Sun Apr 24, 2016 12:51 am
Contact:

Re: [0.16.22]backpressure glitch (?)

Post by Zaflis »

Aeternus wrote:There is something blocking them actually. The splitter they feed has one end of it's output blocked.
The small S-curve between splitters at top left seems to be constantly free for items. I don't see why the 4th inserter desyncs with the rest. Is it maybe just because it is a turn? A straight belt would work but this not?

quyxkh
Smart Inserter
Smart Inserter
Posts: 1027
Joined: Sun May 08, 2016 9:01 am
Contact:

Re: [16.22] Belt back pressure inconsistency

Post by quyxkh »

It seems to me now that if the splitter's chosen output lane for an item is busy and its buffer is occupied it takes a tick to switch. That seems fair enough. To keep the traffic flowing freely put four belt segments on the inserter-drop-to-splitter-input path, not just two. That fits in to most of my station designs without trouble and poses only solvable problems for the rest so I'm happy.:

Twinsen
Factorio Staff
Factorio Staff
Posts: 1329
Joined: Tue Sep 23, 2014 7:10 am
Contact:

Re: [kovarex] [0.16.22] Belt back pressure inconsistency

Post by Twinsen »


kovarex
Factorio Staff
Factorio Staff
Posts: 8078
Joined: Wed Feb 06, 2013 12:00 am
Contact:

Re: [kovarex] [0.16.22] Belt back pressure inconsistency

Post by kovarex »

I re-tested this setup after making different (but related) bugfix of the input priority logic. And it seems to work properly now (by now I mean in the to be release 0.16.29)

Post Reply

Return to “Resolved Problems and Bugs”