Plc Lo3
1. Identify the following elements associated with the preparation of a programmable logic controller program.(assessment criteria 3.1)
a. Statement list
b. Function diagrams
c. Graphical programming languages
Solution: - In PLC statement list: - This is a textual programming language this can be used to generate the code section of logic blocks in PLC program preparation. Its syntax for statements is similar to assembler language and consists of instruction followed by addressed on which on the instruction acts.
A example of statement list used in plc programming. Function diagrams: - It is a graphical language for PLC program. It describes the function between I/O variable and O/P variables. A function is described as set of elementary blocks. I/O variable and O/P variables are connected to blocks by connection lines.
Input and output both blocks will be wired together with connection lines, or links. Single line may be used to connect two logical points of the diagram. An input variable and an input of a block
An output of a block and an input of another block
An output of a block and an output variable
Graphical programming language:- grafcet (graphe fonctionnel de commande etape transition) is a symbolic, graphic language that represents the control programme as steps or stages in the machine or process. It lets users create programs by manipulating program elements graphically rather than by specifying them textually. As the IEC 1131 standard’s sequential function charts (SFCs), which allow several PLC languages to be used in one control programme.
2. Write a programme using logic functions based on relay ladder logic for e.g a motor controlled by stop and start push button switches and for which one signal light must be illuminated when the power is applied to the motor and another when it is not applied.(assessment criteria 3.2)
a. Statement list
b. Function diagrams
c. Graphical programming languages
Solution: - In PLC statement list: - This is a textual programming language this can be used to generate the code section of logic blocks in PLC program preparation. Its syntax for statements is similar to assembler language and consists of instruction followed by addressed on which on the instruction acts.
A example of statement list used in plc programming. Function diagrams: - It is a graphical language for PLC program. It describes the function between I/O variable and O/P variables. A function is described as set of elementary blocks. I/O variable and O/P variables are connected to blocks by connection lines.
Input and output both blocks will be wired together with connection lines, or links. Single line may be used to connect two logical points of the diagram. An input variable and an input of a block
An output of a block and an input of another block
An output of a block and an output variable
Graphical programming language:- grafcet (graphe fonctionnel de commande etape transition) is a symbolic, graphic language that represents the control programme as steps or stages in the machine or process. It lets users create programs by manipulating program elements graphically rather than by specifying them textually. As the IEC 1131 standard’s sequential function charts (SFCs), which allow several PLC languages to be used in one control programme.
2. Write a programme using logic functions based on relay ladder logic for e.g a motor controlled by stop and start push button switches and for which one signal light must be illuminated when the power is applied to the motor and another when it is not applied.(assessment criteria 3.2)