When timer done turned on, close door motor should ON until closed limit switch is turned ON. Ladder logic is a fast and simple way of creating. A lot of the same commands used in Ladder Logic are used in FBD, but it is often easier to read and conceptualize. In Function Block Diagram, program blocks are connected together to create a program. It is a graphical PLC programming language which expresses logic operations with symbolic notation using ladder diagrams, much like the rails and rungs of a traditional relay logic circuit. Function Block Diagram (FBD) The second most popular PLC programming language is called Function Block Diagram (FBD). When the open door limit switch is turned to on, the Open motor door should stop and timer needs to turn on to give time delay of 5s to close door motor. Ladder logic is a programming language that is used to program a PLC (Programmable Logic Controller). RUNG 0016įrom the previous rungs memories, an Open door motor is turned ON with three interlocking like closed-door motor, Timer enables, UP/DOWN motor. Before going to program the PLC with this language, one should know some basic information about it. To open the lift door when it reaching the floor, Binary bits are used to store the status of Third floor PB and third-floor Limit switch. Among several programming languages ladder logic diagram is the most basic and simplest form of programming the PLC. These two numbers form the basis of the number system called the binary system.
Especially if you are just starting out on the journey to learn ladder logic programming. Saving 100’s, even 1000’s of dollars on purchasing a PLC sounds like a good idea.
Rungs are Read Left to Right and Top to Bottom. It is a graphical programming language evolved from electrical relay. Ladder Logic is very easy to understand once you get the hang of a few basic principles. Bit logic instructions use two numbers 1 and 0. A ladder diagram is one of the simplest methods used to program a PLC (Figure 2.3). To open the lift door when it reaching the floor, Binary bits are used to store the status of First floor PB and First Limit switch. Ladder diagram (LD) is the second graphic language to program the industrial control system in the IEC. To open the lift door when it reaching floor Binary bits are used to store the status of ground floor PB and ground Limit switch.
In some cases, if someone pressed the second floor PB/First-floor Pushbuttons (PB), the program will check where the lift is, if it is in the ground floor or the first floor, UP Motor will turn ON to get the lift to the respective floor.įor interlocking, normally closed switch of second-floor limit switch and first-floor switch is used in Rung 0009 RUNG 0010, 0011 In some cases,if someone pressed ground floor PB/First floor PB, the program will check where the lift is if it is in the second floor or the first floor, Down Motor will turn ON to get the lift to the respective floor.įor interlocking, normally closed switch of ground limit switch and first-floor switch is used in Rung 0006 Rung 0007, 0008, 0009