Siemens S5-100U User Manual page 128

Introduction to STEP 5
Block Structure
Each block consists of the following parts:
• The block header that specifies the block type, number, and length
- Generated by the programmer when it transforms the block
• The block body that has the STEP 5 program or data
Absolute
byte
addresses
(in ascending
order)
Programming
Program your blocks as follows (does not apply to data blocks):
1. Specify the block type (e.g., PB).
2. Specify the block number (e.g., 27).
3. Enter the control program statements.
4. Terminate the block with the "BE" statement.
7-8
Figure 7-3. Structure of a Block Header
S5-100U
Synchronization
pattern
Block type
Block number
Programmer ID
Library number
Block length
EWA 4NEB 812 6120-02