[LTN 1.9.6] Trains started to overfill themselves, ignoring created delivery amount

[khadgarion]

I have been using a mixture of LTN and vanilla scheduling with some success up until last night. The vanilla stops are remainders until I can replace them with LTN, because I have really enjoyed using it.

I have my coal supplied power plant requesting 20K coal, with a request threshold of 4k. The mine providing coal has a provide threshold of 30k, and currently has a little over one million coal in storage. This was working like clockwork; The coal power plant would request 4k, LTN dispatched a train to pick up 4k coal, it'd load up and deliver.

Last night I was working on expanding zinc production which requires sulfuric acid. I got my current sulfuric acid production coverted over to LTN, and created a new station at zinc production and turned on the combinator. I had it set for a low request amount (10k) for testing. I noticed the train left the requester station with some fluid leftover. Turns out it had over 23k acid left in the last car (my mistake on the unloading, forgot to setup one of the pumps). I send it back to the requester station, it empties out after I fix the pump, and heads back to depot. A few minutes later, I get a message about the coal power plant delivery timing out, which is strange; That has not happened before (beyond my initial setup, I only have fast inserters so I had to lengthen the delivery timeout to 10 minutes to let it load).

The train that LTN dispatched to pickup 4k coal is now just sitting there gorging itself on coal, and another train has been sent to pickup coal since the first one timed out. I send the first one on it's way, and the second one parks at the mine and does the exact same thing, and fills itself to capacity (4 cargo wagons full).

The only thing I can figure out is the "AND 2 sec inactivity " is messing me up. From what I can tell, this has always been on but has not goofed up my LTN setup until now... The sulfuric acid setup is probably just coincidental timing. The LTN mod settings are all default, except for the delivery timeout of 36000 ticks. It's possible I may have changed something else (I did fool with the settings after this problem started) but I don't tend to mess with stuff when it is working well.

The coal mine is using only fast inserters to load the coal, with no additional LTN circuitry. This has worked great. Has anyone else had this happen, or have any idea what I may have done to make this break all of a sudden?

Is there any additional information I can provide?

Thanks for a great mod too!

[khadgarion]

I unchecked the "Finish Loading" setting in the menu and train seem to be running as they were before, but I noticed (like the tooltip said) it leaves some inserters hanging onto items. While it's not a big deal for a coal provider, it may mess up other stations.

I remember reading something about using the "read train contents" option in the circuit network settings. Is there a way to know how much a train is setup to deliver (4k, for example) and tell the inserters to stop when the train reaches that amount?

[eduran]

LTN does not in any way change how inserters work, so by default they will fill any train to capacity or until it leaves. It's strange that it worked differently for you.

To get stations to stop loading once the scheduled amount is on the train you have to use filter inserters and the output from the LTN-stop's constant combinator (it tells you what is supposed to be on the train). Have a look at this for an example:

Provider

This station can handle multiple items and will only load the amounts scheduled to load.
Note: Overloading up to 1 cycle per inserter is possible, use locked slots per wagon signal.

0eNrtWt2OozYYfZXKlxWswDaERFWfYLWq1L2rRogEJ7EWMDIm6miUd68NzSRr4vAZ7SU3kyHA4fj4fD/B/kD7qmet5I1Cuw/ED6Lp0O6fD9TxU1NU5jv13jK0Q1yxGgWoKWpzVIkT7xQ/hEoWvAk7JVp0DRBvSvYv2sXXAI5wOLNOhW3RdfzCwlaKCy+ZfEDD17cAsUZxxdlIbjh4z5u+3usrd/EnaGfonM4q1B+VflYrOn2XaAwLjRTGOEDv+hNr9JJLdhhPYsPXAsVw0AgMSsCgGRiTgjFTMGYCxqRgzBSMCZ+kDRQTPkUZFBLOcguFhItpPAfDhE96DI4juDljcBh5RFH8GEaMVWMKeWKk7ZdkAI2+JBpV57ZmhO3MBbH5c5KMNY85hZcaP3l4qPmCxte36/UZk8fgKw4/wiOvFJMhbzom9T8vOIUjqYeh0oGikqLK9+xcXLiQ5qYDl4eeq1yfKz+RTJ5WhUnakbmrbgtZKHM9+sNkzlty9brp9qBalCwXx1y0TJ8f7tXOGMaX3wjypu1VPknxFy5VX1T3LD9eEf6Nro4JkKycyL8By58AjZAtNAKxmMSZi0nqbYTNagRfI2CnETbe8mer/HPyU9v9qUv+DBiHm1+UkHHkYrIFMkmWMdEPtpgQBxMcAZmkCzXJ7NnZupjE3sGRrsExFxypbQTskh97y5+s8s/Ij2NbfuqSH9os0oVxuLW7FacR/JtFuhphzggYLH/iLX+8yj8nv12FsLMKpcA4jBdWZrtZJE4jbIBM8EImKdiSmbcl8WrJOUsmYPm33vJHq/y+8hNXr04iX/lX9WfVt7sR4vrNRmJYFoyWJUFi12Xi+qFEMDAdR78oHRPXWwQCbBUXVihi96zE1bMSCiOysEAR+7UWdc6Nd8+01qe5ECUpWH3vl4prwzqrPrw83dvEQnJ1rtmwWinqPW+GkU3Uv73dikHS30HvQg7Uj1x2HsNnxeGMRgH+n4BQK/qgL/pd3yN65SXqiOohLDU6Bgi7dM/Ars9erTKH40CerR85vY/h7tjcnTrUDhfH7UuOg4FfUPzM17B49DRE0byrM29OP5vCjso/zem+Y/pRlZBaFSV75lNFqKt60ejlNgHXyl/0bNImAnWsKXMl8gEQ7Y5F1bFAT2VR5kcp6tv3ZjABGg5y89SWlXABv3slFMsyruaC3vutmpW8r0NWaXipxWlFxZ7uK7jlE2d5f/7W/i0ALmc5fxlR7EuWLOGK7RUGnDnJY5s8frJMCEwxlHgOb9HopqVmml0cg6V42ioGwOijnmMD2Ow5R3tCyORNaOLieG8rbwnqZWGN458ozmeJsVFy7GSahH2lms99R6E6S9adRVWO6bM3uZNGUfSwueltQZrUMz3sf9o9bLjSrVSxZ5oa+vr9229/3XY+BeiiuQ/DSynFySahqTb79T/NDN90

Copy blueprint

Usage:

• Connect the chests to the input (lamp)
• (Recommended) Connect a constant combinator to the input setting provide threshold, limit train size, asf
• When a train arrives the expected train inventory is sent from the output alongside the train composition.

The alternative is to disable "Finish Loading", as you did. As long as your stations only ever provide one type of item, this should also be fine. Hanging inserters only become a problem with mixed provider stations.

[Optera]

Disabling "finish loading" WILL BREAK / PREVENT any multi item or not 100% full delivery.

I highly recommend using smart station designs.
With LTN smart loading is as simple merging expected inventory from ltn output and current inventory from stop read train inventory.
See Design thread for blueprints and more detailed explaination.

[khadgarion]

LTN does not in any way change how inserters work, so by default they will fill any train to capacity or until it leaves. It's strange that it worked differently for you.

I agree, it is strange that it was working. I don't know what exactly happened there, but I am going to modify all my existing stations that do not use filter inserters to do so, that way I can turn the Finish Loading option back on. I did build a multi-provider station, but it's supplies are not used yet so it's not really doing anything and I would like it to work.

Many of my LTN stations are a mess because I was learning how it worked (simple is best when learning!) and now that I am ready for more advanced usage I will do it the correct way, with filter inserters.

Thanks to the both of you for replying, much appreciated!

[zysnarch]

I've had this problem a while on all of my stations, and I've only just dug into what's happening.

I have a smart requester station, requesting X-3000 iron ore, where X is the current contents of the station.
- When the requester drops down to 2000 iron ore remaining, the request reaches -1000, triggering delivery #1 for approx 1000 iron ore.
- Meanwhile, the requester has consumed more iron ore. When it drops to 1000, the request becomes -2000. LTN then creates *another* delivery.
- There are now 2 deliveries to fulfill the 2000 iron ore request, though each train can and will attempt to supply 15000 ore each. (I have "Finish loading" enabled).
- Both trains complete their delivery, supplying a total of 30000 ore and overfilling the station (it can only hold 15000 ore).

I believe what's happening is that LTN is not accounting for the actual size of the delivery - only the expected amount. Both deliveries have train schedules looking for approx 1000 iron ore. When the requester reaches 2000 iron ore, LTN thinks that the first train will only supply 1000 of that request, and that I need another 1000 from another delivery.

Is this a bug? If not, is there a way to configure my stations to prevent this? (I could set the train limit on some stations, but other stations can handle multiple trains, so I'd still encounter this problem.)

[Optera]

merged into topic with same answer

This is working as intended. Your provider loading over 10 times the requested amount is the bug.

1) Use filter inserter designs instead of dumb inserters for requester AND provider.
2) Set threshold signals at every station to a full train load to maximize train utilization.

[zysnarch]

Thanks for the response. I completely misunderstood the purpose of the "Finish loading" option.