Introduction to Industrial Automation

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Chapter 4

Logical Design of 

Automation Circuits

4.1   Introduction to Logical Design of Automation Circuits

In Chapter 3, we investigated the design of automation circuits based on empirical methods, rely-

ing mainly on acquiring knowledge from simple to more complicated circuits that are commonly 

utilized in the industry. In Chapter 4, the focus will be on a systematic method for the design of 

automation circuits, especially for the cases of complicated automated demands, where principles 

from Boolean logic can be adopted to simplify the overall design methodology.

In the Boolean logic approach, everything that is being utilized has two states, such as an ON 

or an OFF state (for example, an electrical switching contact can be either open or closed) or a 

relay can be energized or de-energized. In Section 1.1, where the industrial system was defined, it 

has also been mentioned that various components participating in such a system have two states of 

operation. Thus, since automation circuits are mainly considering devices with two states, they are 

directly compatible with the Boolean logic. Furthermore, methods from Boolean logic design can 

be adopted and applied in the design of automation circuits. In general, there are multiple, specific 

methodologies for designing Boolean logic diagrams, e.g., the methods based on sequential step 

diagrams, the cascade method, the Huffman method, and others that mainly consist of variations 

of these methods. Each one of these methods has its own specific advantages and disadvantages 

and can be applied to problems of a specific size, while they all have their own level of complexity 

during application.

From all these methods, the most general approach which is not dependent on the specific 

kind of automation and is based on the state diagrams, will be presented. The specific aim of 

this chapter is to highlight these general methodologies that are directly applicable in  industrial 

automation, and not to confuse the reader by presenting numerous design approaches and fur-

ther extend theoretical analyses of them that will not be directly applicable in real-life industrial 

problems. From this point of view, the presented state diagram approaches will act as a generally 

valuable tool in designing automations for complex and large industrial processes.

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