Process control system in the boiling house of sugar refinery in Lovosice
For sugar crystallisation automatic control in boiling house of sugar refinery in Lovosice, the staff of our research group designed the complete control system and its software equipment. Installation of instrumentation associated with facilities was performed by the staff of the sugar refinery.
Boiling house of sugar refinery in Lovosice with operators' computers view in detail
On the basic level the control system was formed by five PLCs (Alfa Laval SattControl OP 45 SB). Their connection with the technological process was realised by 150 digital and 70 analogue signals. The PLCs were equipped by algorithms for PID regulatory control, it was possible to configure up to 8 regulators in each of PLC. Sequential control formed base of the control algorithm of sugar crystallisation. Two operators' PCs belonging to the superior control level were installed directly in control room of the boiling house, other PCs were installed in control room of the front production line, in the operating laboratory and in the room of the production manager. The communication backbone was formed by the SattBus industrial bus. It should be noted that such a computer network management were not unusual at all at that time.
Diagram of connection of PLCs and operators' PCs of the control system in the boiling house of the sugar refinery in Lovosice
Operators' computers enabled monitoring and actuation of technological process. It was possible to switch between displays for each part of the technology by mouse and functional keys (there were approximately 20 basic displays with other 40 ones for displaying of trends, setting of controller parameters, setting of process parameters etc.). Alarms and information for operators were partly displayed on screens of PCs, partly were notified verbally by sound equipment of computers.
This concept of process control as verified in Lovosice in 1992 has been used in most of the existing sugar refineries over the next few years and in the few remaining plants, it is still in operation till today.