Hi friends, today we are going to explore mathematical computations in ladder logic. Like in any programing language you should find logic and mathematic computations, here in PLC programming you often need to process the input data that is collected from reading analog devices like temperature, level, flow et cetera. Then you need to run some calculations on this data to derive some other variables for deciding to run or stop some device or even to determine analog output to output to analog device i.e. valve or actuators. In the following sections, we are going to explore the mathematical functions and their input operators and outputs as well. Then we will show how to utilize such functions in ladder logic with simple examples and as usual enjoy practicing them thanks to the PLC simula ...
Hi friends and hope you are all very well. Today, we are going to deal with one of the most important and common problems that would be there in everyday tasks in industry and its solution. The problem is the safety of equipment and operators by preventing the machine from running under specific conditions for realizing the safety of equipment and human as well. Not only does it fulfill safety but also it is for performing the designed sequence of operation. If there is a problem, then it should be the solution for it. the solution is what so-called “Interlock”. So, what is interlock? And why do we need it? And how we can design a good interlock? Well! We may find such concerns exist in two aspects which are safety and operation sequence. In the f ...
Hello friends! We hope you are very well! Today we are here for complementing our knowledge with one of the most important topics in PLC programming and practice its implementation in PLC ladder logic programming. Our topic today is about counters which help us to know the production size at any time, the repetition of specific tasks and events. Many real-life situation problems need counter like garage capacity should be tracked by using counters to report how many cars are inside and if there is room for incoming cars or it's full. Another critical problem is to count the repetitive tasks and events in manufacturing. Furthermore, counting products and pieces for taking an action like performing maintenance, stop operation, turn over to next prod ...
Hello friends! I hope you are doing very well, today we have a very crucial topic which is “timers”. Yes! Exactly like what comes to your mind. For running equipment i.e. motor at a specific time and/or for some amount of time we need timers. Timers are used even before PLC in classic or relay logic conventional control. However, there is a big difference between capabilities and limitations between using physical timers in classic or old fashion relay logic and using software timers in PLC. By completing this article you will be able to know what are timers and their types and applications. In addition, we are going to show off how to use timers in ladder logic programming with examples.
What are timers used for in industrial applications?
Well! ...
Hi friends! I hope you are doing well! Today we are going to learn and practice a new topic which is a very crucial technique in plc programming. the topic is called “latching”. We mean by Latching to keep the output running starting from the instance of giving a kick-off command until we hit a command to stop running of the motor. Imagine my friends, operator wants to start a motor by hitting a start push button and want the motor to keep running and leave and go for doing another task or job. And then it keeps running until the operator wants to stop it. The problem here is that, once the operator releases his hand away from the push button, the motor automatically stopped and that is not like what the operator wants to do with the motor. To clear the problem that we are going to solve, ...
Hi friends, how are you doing? Today will integrate all of what we have learned so far in this series to build the first project based on ladder logic programming. Because we all are interested in industry, we pick one industrial project, Bottle Filling and Capping Projects, which is very common today. The problem we are going to solve today is bottle filling and capping. We have learned all basics of ladder logic including contacts and coils operation, logic gates, rising and falling edges, timers, and counters. So, today we will utilize all of these components to implement a complete ladder program of filling and capping problems.
Operation and Logic of Bottle Filling and Capping Process
For simplifying the operation of the process of filling and capping, fig. 1 shows the process flow ...
Hello friends, How are you doing? Today, we have a very interesting topic of PLC ladder programming which is how to detect the transition between true and false and from low to high?. I know you are asking why do we need that? Well! Imagine my friends, we want to start a motor when the input signal state changes from high to low or from false to true. Let us give two examples to highlight the edge detection techniques. Good examples of using edge detection-based logic are timers and counters. In counters, they are energized to count up or down when a signal appears and the same for timers. Figure 1 shows the difference between using the edge to control a motor. In the top part, the motor is controlled by an input switch. the output is ON and OFF b ...
Hello friends! I hope you are all very well! I am so happy to meet you today to continue learning and practicing PLC ladder logic programming. In an earlier part, we already have gone through the very basic logic gates of “AND”. “OR”, and “NOT”. Today we are going to resume the simulation of logic gates. We have started and gone through simulating the basic logic gates which are “AND”, “OR”, and “NOT” as they are the most important basic logic gates by which we can form other logic gates. However, because the logic of large-scale projects is getting more and more complicating, a lot of time we have to use the other functions to do tasks faster. For example, we have shown in the logic gates article that, XOR can be used to compare two inputs and ch ...
Hello friends, I hope you all are doing great. In today's tutorial, we are going to design logic gates in PLC Simulator. It's our 4th tutorial in Ladder Logic Programming Series. We come today to elaborate the logic gates with comprehensive details for their importance in PLC programming. you can consider logic gates as the building blocks of ladder logic programming. Like every time we start with telling what you guys are going to have after completing this session? For those who like to buy their time and calculate for feasibility, I’d like to say by completing this article, you are going to know everything about what types of logic gates, how they are designed and how they work, how you can translate the logic in your head into the logic gate a ...
Hello friends, I hope you all are doing great. In today's tutorial, I am going to create the first Ladder Logic Program in PLC Simulator. It's 3rd tutorial in our Ladder Logic Programming Series. In our previous tutorial, we have installed PLC Simulator and now we can say our lab is ready to learn and practice. So let us get to work and get familiar with the ladder logic components.
After this article, you will have a complete understanding of PLC contact and coil including their types and possible causes. Because they are the building block of any rung of a ladder logic program. So let us start with ladder logic rung components.
Ladder Logic Contact/Input
In ladder logic programming, a contact represents the input of the system and it could b ...
