Programmable logic controllers

Definition

Programmable logic controllers (PLCs) are industrial digital computers designed for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures. These devices are crucial in computer integrated manufacturing systems as they allow for flexible and efficient control over various processes, enabling quick adjustments and reprogramming when necessary. PLCs operate in real-time and are robust, making them ideal for environments where reliability and speed are essential.

5 Must Know Facts For Your Next Test

1. PLCs can be programmed using various languages, with ladder logic being the most common due to its resemblance to electrical wiring diagrams.
2. They are designed to operate in harsh industrial environments, featuring rugged construction that protects against dust, moisture, and temperature variations.
3. PLCs support modular design, allowing users to easily add or replace components like input/output modules without having to redesign the entire system.
4. Real-time processing is a key feature of PLCs, enabling them to respond instantly to changes in input conditions and execute commands without delay.
5. The integration of PLCs into computer integrated manufacturing enhances productivity by allowing for automated monitoring and adjustments of manufacturing processes.

Review Questions

• How do programmable logic controllers enhance the efficiency of computer integrated manufacturing systems?
  • Programmable logic controllers enhance the efficiency of computer integrated manufacturing systems by providing real-time control over various automated processes. Their ability to be reprogrammed quickly allows manufacturers to adjust operations based on changing production needs or system inputs. Additionally, PLCs facilitate seamless communication between different machinery, which helps streamline workflows and reduce downtime in manufacturing operations.
• Discuss the importance of ladder logic programming in the operation of programmable logic controllers.
  • Ladder logic programming is essential for the operation of programmable logic controllers as it offers a user-friendly method for designing control circuits. Its graphical representation mimics traditional relay logic diagrams, making it accessible even for those familiar with basic electrical concepts. This programming language allows engineers to easily implement complex control strategies and troubleshoot issues, thus increasing the efficiency of programming PLCs and ensuring smoother operations in automated environments.
• Evaluate the impact of modular design in programmable logic controllers on modern manufacturing processes.
  • The modular design of programmable logic controllers significantly impacts modern manufacturing processes by providing flexibility and scalability. Manufacturers can customize their PLC setups based on specific needs by adding or replacing modules without major disruptions. This adaptability enables companies to quickly respond to market demands and technological advancements. Moreover, modular PLCs reduce maintenance time and costs since individual components can be serviced or upgraded independently, leading to increased overall productivity.

Related terms

Input/Output Modules: Components of a PLC that connect to the external environment, allowing it to receive signals from sensors and send commands to actuators.

Ladder Logic: A programming language used to develop software for PLCs, resembling electrical relay logic diagrams.

SCADA Systems:

Supervisory Control and Data Acquisition systems that monitor and control industrial processes, often interfacing with PLCs for data collection and control.