Practical Tips and Techniques
Looking at a stop-start jog circuit in the PLC will help us understand the differences in hard-wiring the circuit and programming. Basic Start Stop Circuit Let’s start with the primary start-stop circuit. Here is what it looks like hard-wired. (Physical switches wired to outputs devices, such as motor contactors and relays.) When the start pushbutton … Read more
In part 1, we looked at writing PLC programs to control a traffic light using discrete bits and timed sequencing using indirect addressing. We will now look at how we can use indirect addressing for inputs and output to control the sequence in the program. Let’s look at an example of controlling pneumatic (air) cylinders. … Read more
What is the best way to program a PLC? My answer is simple. The best way is one in which someone can look at your program and understand it. I cannot stress the need for good documentation of your program enough. The best programs are ones that I can return to after several years and … Read more