Introduction to Industrial Automation

8.3.7   SCADA  Systems

The establishment and broad utilization of communication networks in the field of industrial 

automation brought, along with the economic and operational benefits, the development of the 

supervisory control and data acquisition (SCADA) systems. Nowadays, a SCADA system is used 

(a)

(b)

Figure 8.11  The AS-I network can interconnect sensors and actuators (a), as also simple devices 

(buttons, switches, etc.) (b) at the machine level.

---

Industrial Networks of PLCs 

◾

 

369

to monitor and control an entire production system or plant and consists of a series of operations, 

the collection of information, the transfer of it to a central station through the network, the car-

rying out of the necessary data analysis, the indication of data in a number of virtual “screens”, 

and finally the possible control actions. It is essentially a large software package-tool, which col-

lects all the required information through the network from the controlled system, so that it can 

implement a number of operational functions while visualizing it to the user in a friendly and 

realistic approach. The most significant feature of SCADA systems is the ability for downloading 

and storing data, graph production, the graphical display of the process with simulated motion of 

the machines, the announcing of alarm situations, the presentation of real-time values in active 

fields, the recording and printing of normal or exceptional events, the statistical processing of 

data, the status monitoring of the overall communication network, the communication with the 

external databases, and many other features that provide the end user with a direct overview of the 

controlled industrial process. It is obvious that the control actions applied by a SCADA system 

can be automatic or manual. This means that an operator can start or stop machines through the 

SCADA system while Figure 8.13 shows an example of an industrial process depicted in a SCADA 

software environment.

Siemens S7-300

Class-1 DP-Master

PC(W/Class-2

DP-Master function)

PROFIBUS

i-7550

PROFI-8455

RS-232

RS-485

RS-232

RS-232

temperature

sensor

i-8K

module

i-87K

module

Remote I/O solution