Practical Tips and Techniques
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
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
The Machine Simulator (MS) is part of the EasyPLC software suite. It has many built-in machines that can be programmed. The chain conveyor is one of these machines. It will transfer large and small boxes on the line to different locations. The productivity series of PLCs will be used to program this virtual machine. Using … 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
PLC outputs are the next component of our PLC block diagram. The PLC program will control the outputs of the PLC. Controlling outputs is one way to get the inputs to change. We will be looking at digital and analog outputs that can be wired to the programmable logic controller. PLC troubleshooting outputs will also … Read more
