Practical Tips and Techniques
Building a PLC program series will take you through developing and programming PLC logic. This six-part series was released almost seven years ago but is still relevant today. Each part will add and build upon the previous step. This series will look at different ways to solve the same machine logic. Using discrete inputs and … Read more
Logic circuits in a PLC ladder logic program are either on or off. The inputs change, which will affect the outputs. This can be expressed in a timing diagram. The timing diagram or chart will show you how the ladder logic program will respond to the changing states of the inputs and outputs. This visual … Read more
The Machine Simulator (MS) is part of the EasyPLC software suite. It has many built-in machines that can be programmed. A simple conveyor is one of these machines. This is usually the starting point for learning about the machine simulator. This conveyor example will use two digital inputs and two digital outputs. A pallet will … Read more
Developing a programmable logic controller (PLC) program can be broken down into five steps. These programming steps are as follows: Five Steps to PLC Program Development Step 1 – Define the task Step 2 – Define the Inputs and Outputs Step 3 – Develop a logical sequence of operation Step 4 – Develop the PLC … Read more
Programmable logic controllers (PLC) use a cyclic scan. The time that it takes to complete one scan is called Scan Time. Typical scan times range from 10 milliseconds to 10 microseconds. This translates from 0.01 to 0.0001 seconds per PLC scan. Understanding how the program scan will help us in programming and troubleshooting the PLC. … Read more
PLC memory is very similar to personal computer memory. There is the operating system and firmware of the processor and connected modules. PLC programs and data that are used by the program are also stored in the memory. We will now look at the basic understanding of memory in the PLC. Looking at two examples … Read more