Programable Logic Controller Basics Explained - automation engineering

The video script begins by discussing the growing reliance on automation for mechanical and electrical systems in commercial and industrial settings. It introduces the sponsor, Telecontrols, a leading manufacturer in the automation industry since 1963, known for their compatibility with various PLCs, HMIs, and controllers. The script explains that a PLC (Programmable Logic Controller) is a small computer that executes pre-programmed outputs based on inputs and specific rules, reducing manual intervention. It also contrasts PLCs with older relay-based systems, highlighting the advantages of PLCs in terms of ease of programming, flexibility, and compactness.

This paragraph delves into the components and operation of a PLC. It describes input modules that connect field sensors to the PLC, including digital and analog inputs. The central processing unit (CPU) of the PLC is likened to the brain, holding the program and making decisions based on input signals. The CPU consists of a microprocessor, memory chip, and integrated circuits for communication. Output modules are also explained, which control devices like indicator lights, solenoid valves, and motor starters. Additional components like a battery for power failure, a user interface, a time clock, and a power supply are mentioned. The basic operation of a PLC is outlined, including input scanning, program scanning, executing logic, updating outputs, and housekeeping tasks.

The script provides examples of how PLCs can be used in temperature control systems. It describes a simple setup with a bi-metallic strip temperature sensor controlling a boiler, highlighting the PLC's ability to incorporate time functions to prevent unnecessary operation during unoccupied periods. A more sophisticated example involves a thermistor and an actuator valve, using a PID (Proportional Integral Derivative) control loop for precise temperature regulation. The paragraph also discusses a control strategy known as an optimizer used in commercial buildings, which learns and adjusts heating or cooling systems to operate at optimal times based on the building's thermal response and occupancy schedules.

The final paragraph outlines the advantages of PLCs, including local storage of control software for continued operation during system failures, software-based connections reducing the need for physical wiring, ease of reprogramming, and faster fault finding. It also mentions the ability to load the same program onto multiple PLC units and expand inputs and outputs with additional cards. The script concludes with an invitation to follow the channel on social media platforms and to continue learning about controls and electrical engineering through recommended videos.