Practical Tips and Techniques
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
Programmable Logic Controllers (PLC) will scan very quickly. This can be anywhere from 1 to 20 ms, translating into 1000 to 500 times each second. But what exactly is a scan? A scan is when the PLC will complete the following: Read Inputs: Look at all of the inputs to the programmable controller. Digital, Analog, … Read more
I have always been an old-school programmer. Hardware in front of you hooked up to all of the I/O. I have recently looked at the automation direct do-more designer software solution. The Do-More Designer Software will allow you to build your ladder logic, download it into a simulator (which comes with the software), and run … Read more
Grey Code Grey Code is used because only one bit of data will change at a time. The following chart shows the conversion of Grey Code to Binary. Number Binary Code Grey Code Number Binary Code Grey Code 0 0000 0000 8 1000 1100 1 0001 0001 9 1001 1101 2 0010 0011 10 1010 … Read more