Introduction to Industrial Automation

Figure 3.29  An alternative automation circuit for the Y/

Δ

 start-up of a motor, and an example 

of the localization manner of switching contacts and relays.

---

106

 

◾

  Introduction to Industrial Automation

real implemented circuits present some challenges, and show how difficult the checking of their 

proper operation (or logic) is, especially when the full automation in the rack or a cabinet is not in 

the electrical drawings. This difficulty increases in the case of large industrial circuits that can be 

geographically spread over large areas, while containing a large number of buttons and switches on 

the same rack or cabinet, or in a remote control panel. After manufacturing the industrial switch-

gear, the installation of the automation system in the production area takes place. If the industrial 

automation design involves sensors, then the installation should also contain the placement of 

sensors and their wiring with the switchgear or control panel.

Overall, it should be mentioned that the development of an industrial automation system 

involves the following stages:

 

◾

Collection of the operational requirements for the complex machine or production line

 

◾

Design of the automation circuit based on the gathered regulations

 

◾

Calculation of the circuit components (e.g., power relays, thermal overload relays, auxiliary 

relays, wires, power supplies, operating voltages, etc.)

 

◾

Manufacturing of the electrical industrial switchgear

 

◾

Installation of the industrial switchgear, which includes:

–  Placement of the switchgear

–  Power wirings (e.g., motors)

–  Low-power wirings (e.g., sensors, actuators, signaling devices, control buttons and 

switches in control panels, etc.)

–  Testing of the whole system and tuning of sensors (e.g., position tuning of the limit 

switches, photo cells, etc.)

 

◾

Implementing and programming, where the automation or parts of the automation in PLCs 

are needed and perform the necessary wiring connections from and to the PLC and the rest 

of the automation equipment, as described previously.

Power circuit

Automation circuit

Power relay

Thermal

overload

relay

Fuses

Power 

Stop

Start

Motor

Power supply

Power circuit

Automation circuit

Fuses

Power

switch 

Stop

Start

Motor