Section 2--511. Tender of Payment by Buyer; Payment by Check.

(1) Unless otherwise agreed tender of payment is a condition to the
seller's duty to tender and complete any delivery.

(2) Tender of payment is sufficient when made by any means or in any
manner current in the ordinary course of business unless the seller
demands payment in legal tender and gives any extension of time
reasonably necessary to procure it.

(3) Subject to the provisions of this Act on the effect of an
instrument on an obligation (Section 3--802), payment by check is
conditional and is defeated as between the parties by dishonor of the
check on due presentment.