A float is also an amount of money that one keeps in the till of a retail operation. It is limited to a certain amount, and any taking above this are taken out, and either banked or (hopefully) locked in a safe. It is normally made up of set amounts of various denominations, whether coinage or notes, and serves to ensure that the shop or store has enough change each day to commence operations.

I am confused, however, as to how a float operates in a 24/7 operation.