The present invention is a method of judging whether a substrate is accurately placed at a predetermined position when placing the substrate at the predetermined position on a plate to perform heat treatment or cooling treatment therefor. A multiplex communication system is made up of a plurality of communication groups including a plurality of communication lines and a data repeater. A positioning device is mounted in the case for retaining the key cylinder in place. Additionally, two or more pixel cells of an array may share a floating diffusion node and reset and readout circuitry.