This paper presents a design experience of a supervisory control system. For effective programming of job commands, a petri net-type graphical language (PGL) is proposed applied to various tasks having concurrency and synchronization. Our PGL based supervisory control system is composed of PGL editor and PGL compiler; PGL editor is designed to help us to generate a job program using graphical symbols. PGL compiler includes analyzer, scheduler, and tranlator, PGL analyzer prevents a deadlock or resource allocation of unit cell, PGL scheduler generates a adequate job sequence of unit cell. and PGL translator translate the scheduled sequence into the iob program of each unit cell.