That makes a lot of sense, thanks. It is actually a brilliant setup.kovarex wrote: ↑Fri Nov 03, 2023 1:07 pm By default you will multiply the contents by -1, not -2. You sum this with the required values, this means, only the positive values are the missing values (You need more than you have).
And the filter inserter, when configured to set filter based on circuit signals only works on positive values, so it only picks items that are needed.
The multiplication by -2 is used in a more advanced setup, where you only want to call the supply train when there is more than 1/2 of items missing, so it doesn't come for a single individual missing item.
I think in this screenshot the train station will indeed only be called when half is missing from an item type. However, I think the filter inserter will also stop inserting when half of the items are loaded.
It could just be the screenshot is incomplete though and was only meant to showcase logistic groups applicable to constant combinators. In which case I will stop trying to analyze it