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 move back and forth on the conveyor. When the pallet is detected on each end it will stop and reverse direction. If both motors are started at the same time, the motors will burn up. This will be demonstrated. The machine simulator will allow you as the programmer to make mistakes before trying your program in the physical world.
The Click PLC will be used to program this virtual machine. Using the Click Plus PLC, we will connect the simulator to the simple conveyor machine. This will be done using Modbus TCP (Ethernet) for communications. Using the five steps for program development we will show how this is programmed. Let’s get started. Keep on Reading!
Developing a programmable logic controller (PLC) program can be broken down into five different 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 program
Step 5 – Test the program
These five steps to PLC program development will help you in understanding, programming, and troubleshooting your automated machine.
We will be looking at each of these steps in a little more detail as we discuss the PLC programming development. Let’s get started. Keep on Reading!
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.
The simplest scan cycle of a PLC consists of 4 steps. Read inputs, execute program, diagnostics, and communication, and update outputs.
We will be looking at each of these steps in a little more detail as we discuss the PLC program cyclic scan. Let’s get started. Keep on Reading!
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 of PLC specifications. We will see how the program is stored and how long data memory will remain when the PLC is not powered up. Let’s get started. Keep on Reading!
PLC inputs are one component of our PLC block diagram. The output actions of the PLC will be controlled based on the inputs. We will be looking at digital and analog inputs that can be wired to the programmable logic controller.
We will be looking at wiring of a normally open (NO) push button, normally closed (NC) push button, 3 wire PNP sensor, and an analog sensor to the PLC. These will all be sinking inputs. Let’s get started. Keep on Reading!
Invented in 1968 by Dick Morley, the programmable logic controller (PLC) is a simple rugged industrial computer. This free plc training series is designed for everyone to learn about these controllers. PLCs are constantly evolving and continue to be the best option for a variety of industrial automation applications.
Even though the PLC is changing, core items remain the same. We will be discussing this in more depth for each of the components mentioned in the picture above. Let’s get started learning about PLCs. Keep on Reading!