MAKING A SMARTER DRYER SYSTEM - AN EXPERIENCE WITH SMART VALVES AND OPEN SYSTEMS

In May 1995, the steam and condensate system for a linerboard machine was upgraded. The controls were removed from a panel and implemented i n a new distributed control system. This control system is linked syst em. This control system is linked to a scanning/control system on a st andard, ''open'' LAN using IEEE 802.3 TCP/IP communications. All the v alves were refurbished and equipped with ''smart'' digital positioners . In addition to normal analog control signals, the HART protocol is b eing used to pass actual valve positions to the DCS for display to the operator.