PLC Automated Pneumatic System

Introduction

During my third year at university, as part of (EG6013) Industrial Automation Systems Assignment, I had to create an operating system with PLC that could be implemented in industrial applications. This involved the development and improvement of a practical system, the creation of a PLC ladder program and simulation, and a fully pneumatic system build, testing and discussion.

There were no available conveyor belts at university, so pistons were used as an analogous representation instead. With this in mind, this system is composed of:

• 2 pistons: conveyor belts, representing the motion of the boxes

• 2 Valves: to control the pistons motion

• 2 piston Sensors: to always detect the position of the piston

• 1 proximity sensor: to count the number of times the piston moves

• 2 lamps: to display the counter and 10 second timer.

• 3 switches: To control the start, stop and reset functions.

How it operates?

The start switch will initialize the PLC, once activated the first piston will be actioned and retracted until the counter counts 10 times, representing 10 small boxes moving, once it reaches the limit the system will initialize a stop timer for 10 seconds.

During those 10 seconds, the second piston which is active will retract after 5 seconds, representing the bigger box with the 10 small boxes inside leaving.

After 5 more seconds the first piston along with the second piston will be activated at the same time, restarting the whole process. The reset switch can be used to reset the counter

Based on the results from the simulation and physical testing the model operates as desired. Using the same ladder program, it can be implemented in an industry that makes use of conveyor belts, showing the simplicity and practicality of PLC and ladder diagram programming as well as the use of pneumatic tools to simulate such large systems in smaller and cheaper scale.

System can be improved with the use pressure regulators allowing for controlled speed and force of the pistons, depending on the object that is being carried.