Process control device and process control method using a medium with rewritable marking technique

摘要

A process control method allowing an operator to readily confirm an order of operation processes includes steps of: reading magnetic data of a control card when the control card is inserted; transmitting completion data based on a lot number identified from read magnetic data to a host computer; receiving update data by the host computer; writing next process data in the received data as a visually recognizable image on the control card; and writing the next process data as a visually recognizable image based on process data identified by the read magnetic data when a predetermined time period passes without receiving update data.