1. INTRODUCTION TO FBD - Function Block Diagram by ( LOGO ) Revision 2

2. Program Representation - FBD »The graphical representation of a control task using symbols to DIN 40700 and DIN 19239 »Inputs are arranged on the left side while outputs on the right FBD - Function Block Diagram & I 0.0 I 0.1 Q 4.0

3. FBDFBD OPERAND + OPERATION OPERATION + OPERAND = Q 4.0 Operation And Operand & I 0.0 M 80.0

4. Program Execution PLC Scan Function: »Read the status of all inputs and outputs »Examine the application program instructions »Execute the control program

5. The Operand Areas : »I (Input) Interface from the process to the programmable controller »Q (Output) Interface from programmable controller to the process »M (Memory/Flag) Memory for intermediate results of binary operations

6. Hardwire and PLC Wiring Diagrams

7. How Does a Programmable Controller Work? Power Supply Program Memory Processor Input modules Output modules 24 VDC GND Sensors Actuators / Annunciators

8. Steps of Operation »The sensors are connected to the INPUT MODULES »The processor in the CPU MODULE executes the program and scans the individual input for presence or absence of voltage »Depending on the state of the inputs, the processor directs the OUTPUT MODULES to switch voltages »The ACTUATORS or ANNUNCIATORS are switched “ON” or “OFF” according to the voltage states