CJ2 CPU Unit Software User's Manual - CIP ETI

5 Understanding Programming5-4 Function Blocks5-4-1 Function BlocksA function block (FB) is a basic program element containing the programming for a standard processingfunction that has been defined in advance. Once you have created function blocks and saved them in alibrary, you can use them in programming simply by selecting the function blocks that are required forthe system, placing them in the program, and setting I/O parameters. Excellent function blocks cangreatly improve the efficiency of program development.OMRON function blocks conform to IEC 61131-3.FBFBFBOnce function blocks have beencreated, they can be used in avariety of programs.LibraryProgram for Device AProgram for Device AAlgorithms do not need to beverified for function blocks thatare already completed.Rack AparametersFBRack BparametersFBSimply set the parameters foreach of the devices. Features of Function Blocks• ReusabilityA function block can be saved in a library so that it can be easily reused. Once the programmerunderstands the function blocks, the programmer can use them simply by setting parameters. Thisgreatly improves programming efficiency.• Reduced Debugging WorkReusing high-quality function blocks that have already been debugged eliminates the need to debugthem again and thereby reduces debugging work.• Data ProtectionThe variables inside a function block cannot be accessed directly from the outside, so the data is protected.(Data will not be changed unintentionally.)5-40 CJ2 CPU Unit Software User’s Manual