Designing secure networks for process control

With the evolution of data communications in process control, network problems have taken on new proportions. The connections with a DCS and PLC system or from the plant network to the control network are vital to production, yet can be an invitation to problems. This paper looks at several real-life network disasters and discusses strategies for avoiding them. Solutions, including the use of VLANs (virtual local area networks), are discussed. A case history from a pulp and paper mill illustrates how a VLAN can be implemented to protect multiple DCS and PLC systems from each other and from business users.