Statement List (STL) - DCE FEL ČVUT v Praze

Logic Control Instructions
6.5 JCN Jump if RLO = 0
Format
Description
Status word
Example
JCN
Address Description
Symbolic name of jump destination.
If the result of logic operation is 0, JCN interrupts the linear program
scan and jumps to a jump destination. The linear program scan resumes at the jump
destination. The jump destination is specified by a jump label. Both forward and
backward jumps are possible. Jumps may be executed only within a block, that is,
the jump instruction and the jump destination must lie within one and the same block.
The jump destination must be unique within this block. The maximum jump distance
is -32768 or +32767 words of program code. The actual maximum number of
statements you can jump over depends on the mix of the statements used in your
program (one-, two-, or three word statements).
If the result of logic operation is 1, the jump is not executed. The program scan
continues with the next statement.
BR CC 1 CC 0 OV OS OR STA RLO /FC
writes: - - - - - 0 1 1 0
STL Explanation
A I 1.0
A I 1.2
JCN JOVR //Jump if RLO = 0 to jump label JOVR.
L IW8 //Program scan continues here if jump is not executed.
T MW22
JOVR: A I 2.1 //Program scan resumes here after jump to jump label JOVR.
Statement List (STL) for S7-300 and S7-400 Programming
6-6 A5E00706960-01