Introduction to Industrial Automation

Figure 1.15  Typical example of a SCADA screen for process visualization.

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Info critical-data network

Time and control critical-control network

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Time critical-field network

Figure 1.16  The CIM model integrates all levels of industrial production.

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  Introduction to Industrial Automation

has been achieved, a concept that was initially introduced in the early 1970s. With respect to the 

CIM model, an industrial process can be organized in a three-layer hierarchical structure, where 

the lowest layer is comprised of sensors, actuators, and embedded micro-controllers. The middle 

layer is the control layer where the industrial controllers, industrial PCs, and industrial PACs 

are connected. The highest layer is the management level, where the mainframe computers for 

SCADA and resources planning functionalities are located. This three-layer generic structure is 

presented in Figure 1.16. Every level of the CIM model has its own dedicated network, with its 

own technical characteristics for the network speed, the number of nodes, etc., due to different 

operational goals. As an example, it could be desirable to have a real-time control loop in the lowest 

field level and a periodic supervisor control loop in the highest level. It should also be apparent that 

the networks in the various levels are interconnected among themselves in order to allow for the 

transfer of information from the bottom layer to the top ones, and vice versa. Consequently, the 

target of CIM in the industry process is the integration and utilization of the overall information.