2.1.5
STEP 5 Blocks and Storing
them in Memory
Identification
A block is identified as follows:
••
the block type (OB, PB, SB, FB, FX, DB, DX)
and
••
the block number (number between 0 and 255).
Block types
The STEP 5 programming language differentiates between the
following block types:
Organization blocks (OB)
Organization blocks are the interface between the system program and
the user program. They can be divided into two groups as follows:
With OB 1 to OB 39, you can control program execution, the restart
procedure of the CPU and the reaction in the event of an error. You
program these blocks yourself according to your automation task.
These OBs are called by the system program.
OBs 40 to 100 are blocks belonging to the operating system. You
must not call these blocks.
OBs 121 to 255 contain special functions of the system program. You
can call these blocks, if required, in your user program.
Program blocks (PB)
You require program blocks to structure your program. They contain
program parts divided according to technological and functional
criteria. Program blocks represent the heart of the user program.
Sequence blocks (SB)
Sequence blocks were originally special program blocks for step by
step processing of sequencers. In the meantime, however, sequencers
can be programmed with GRAPH 5/4/. Sequence blocks have
therefore lost their original significance in STEP 5.
Sequence blocks now represent an extension of the program blocks
and are used as program blocks.
STEP 5 Programming Language
CPU 948 Programming Guide
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C79000-G8576-C848-04
Summary of Contents for CPU 948
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Page 72: ...Data Blocks CPU 948 Programming Guide 2 42 C79000 G8576 C848 04 ...
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Page 200: ...Contents CPU 948 Programming Guide 5 2 C79000 G8576 C848 04 ...
Page 308: ...Contents CPU 948 Programming Guide 7 2 C79000 G8576 C848 04 ...
Page 324: ...Examples of Parameter Assignment CPU 948 Programming Guide 7 18 C79000 G8576 C848 04 ...
Page 326: ...Contents CPU 948 Programming Guide 8 2 C79000 G8576 C848 04 ...
Page 370: ...Addressable System Data Area CPU 948 Programming Guide 8 46 C79000 G8576 C848 04 ...
Page 372: ...Contents CPU 948 Programming Guide 9 2 C79000 G8576 C848 04 ...
Page 486: ...Contents CPU 948 Programming Guide 11 2 C79000 G8576 C848 04 ...
Page 522: ...PG Functions via the S5 Bus CPU 948 Programming Guide 11 38 C79000 G8576 C848 04 ...
Page 524: ...Contents CPU 948 Programming Guide 12 2 C79000 G8576 C848 04 ...
Page 538: ...Contents CPU 948 Programming Guide 13 2 C79000 G8576 C848 04 ...
Page 546: ...List of Key Words CPU 948 Programming Guide Index 6 C79000 G8576 C848 04 ...