Practical Tips and Techniques
You’ve had this idea for years since you were a kid. You want to be an electrical engineer, and you’re finally going to follow through on it and learn PLC programming to start your career off right! What? That’s what you thought, anyway. But then you started googling around, trying to figure out how to … 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
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
All programmable logic controllers (PLC) have the same numbering system at their core. This is the same with all computers as well. The status of any memory location can be either on or off. A one (1) will represent an on or “True” status and zero (0) will represent an off or “False” status. This … 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