A made-up 52-bin operation, so the screens can be looked at without an account. Nothing here is anyone's real grain.
Bin levels are a ledger. Every load in or out is an entry; the level is the sum. That is why a bin can tell you what was in it last September, and why the drag handle records a change rather than overwriting a number.
The yard shows how full, not what crop. One grain tone on every bin, with the crop as a three-letter code and a filter. Four colours is the measured ceiling for telling categories apart on either surface, so eighteen crop colours would have been a lie dressed as data.
Hopper rings are not linear. On a 14ft hopper the cone holds about 13% of the bin, so half full reads 2.2 of 5 rings, not 2.5. Open a bin and drag the level to watch it.