Industrial automation - basic overview

By G Wilson, Siemens


Published in:

Electricity+Control March 2014 (pages 8-9)



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Totally Integrated Automation is the term applied to a series of products that offers solutions for most industrial automation applications.

Factory industrial automation refers to a group of field devices that communicates to a programmable logic controller (PLC), which reads all inputs from the plant or machines, processes the information and then transfers the result to the outputs. The field devices communicate to the PLC via hardwired signals or a network. A software program collects all the signals from the field devices in the PLC and controls the industrial automation of the plant based on these signals.
Human Machine Interface (HMI) panels linked to a PLC can be used to show graphically if the machine or process plant is operating. These panels are normally located in the field on the PLC cabinet and show only part of the plant operation, not the entire plant industrial automation visualization overview.

Where an industrial factory or plant consists of multiple PLC areas a supervisory control and data acquisition (SCADA) system can be used to link the PLCs, gather data and provide the operators with a plant industrial automation overview.
Distributed Control Systems (DCSs) are recommended for process industrial automation plants that run a continual process. In this instance, the PLC is called the industrial automation system (AS), the SCADA is called the operator station (OS) and the software programming PC is called the engineering station (ES). The AS automatically creates much of the OS visualisation, which saves a great deal of engineering. With a PLC/HMI/SCADA system the software engineering for both the PLC and SCADA has to be done. The factory industrial automation system is generally less expensive and slightly more flexible as there are more PLC options, but for a process plant the hardware and software costs are higher while the engineering costs less. Some industrial plants combine both factory or discrete industrial automation (PLC/HMI/SCADA) and process industrial automation (DCS).


Take note:

  • Factory industrial automation consists of field devices that communicate to a PLC.
  • A distributed control system is recommended for process industrial automation plants.
  • Some industrial automation plants combine factory or discrete industrial automation and process industrial automation.