This document provides an introduction to programmable logic controllers (PLCs) and supervisory control and data acquisition (SCADA) systems. It discusses what PLCs and SCADA are, their importance and functions. PLCs control industrial automation applications through input/output interfaces and signal processing. SCADA systems connect multiple human-machine interfaces to controllers over networks to monitor and operate industrial plants from several locations. The document proposes that combining PLCs and SCADA provides benefits for industrial control and monitoring applications.
6. • Simatic WinCC Flexible June/2007
• SIEMENS LTD EGYPT 2007
• 4
• s
• Application for HMI
• Controller with one HMI devices
• Controller with several HMI devices
• Control with one HMI device
• An HMI device which is directly connected
• to the controller via the process bus is
• referred to as a single-user system.
• Single-user systems are generally used
• near production, but can also be deployed
• to operate and monitor independent part
• processes or system sections.
• Controller with several HMI devices
• Several HMI devices are connected to
• one or more controllers via a process bus
• (e.g. PROFIBUS or Ethernet).
• Such systems are deployed, for example,
• in a production line to operate the plant
• from several points.
7. • Simatic WinCC Flexible June/2007
• SIEMENS LTD EGYPT 2007
• 5
• s
• Application for HMI
• HMI System with centralized
• functions
• An HMI system is connected to a PC via
• Ethernet. The upstream PC assumes
• central functions, e.g. recipe
• management. The necessary recipe data
• records are provided by the subordinate
• HMI system.