Siemens S5-100U User Manual page 192

S5-100U
Block End "BE"
The "BE" operation terminates a block. Data blocks do not need to be terminated. "BE" is always
the last statement in a block.
In structured programming, program scanning jumps back to the block where the call for the current
block was made.
Boolean logic operations cannot be continued in a higher-order block.
Example: Program block PB3 is terminated by the "BE" statement.
Program Sequence
OB1
JU PB3
Unconditional Block End "BEU"
The "BEU" operation causes a return within a block. However, jump operations can bypass the
"BEU" operation in function blocks (see sections 8.2.10 and 8.3.4).
Binary logic operations cannot be continued in a higher-order block.
Example: Scanning of function block FB21 is terminated regardless of the RLO.
Program Sequence
PB8
JU FB21
EWA 4NEB 812 6120-02
PB3
BE
FB21
JC=
BEU
BE
STL
.
The "BE" statement terminates
.
program block PB3 and causes
.
program scanning to return to
.
organization block OB1.
.
.
BE
STL
.
The "BEU" statement causes program
.
scanning to leave function block FB21
.
and return to program block PB8.
.
JC=
BEU
.
.
.
.
BE
STEP 5 Operations
Explanation
Explanation
8-37