PLC 135/WB/WB2/WD is a powerful interface controller for process automation (controlling, reporting, monitoring). It is integrated in the SINUMERIK 88-/880 GA2 and SINUMERIK 840C numerical control and controls machine related functional sequences.
The system program of PLC 135 contains all statements and declarations for internal system functions. The basic program has a flexible interface to the system program and contains pre-tested function blocks written in STEP 5 and assembled to form function macros.
The structure of the PLC 135/WB/WB2/WD makes structure programming essential. The program must be divided into individual, self contained section called blocks. This methods offer following advantages:
• Easy, Lucid programming, even of large programs.
• Easy standardization of program sections.
• Simple program organization.
• Simple program testing.
• Fast, easy modification.
• Easy start up.
A number of block types, each of which is used for different tasks, are available for structuring the user program:
• Organization Blocks, they serve as interface between operating system and user program.
• Program Blocks, they are used to break the user program down into technologically oriented sections.
• Function Blocks, they are used to program frequently recurring complex functions.
• Sequence Blocks, they are special forms of program blocks used primarily for processing sequencers.
• Data Blocks, they are used for storing data or texts, and differ in both function and structure from all other block types.