Statement List (STL) - DCE FEL ČVUT v Praze

6.10 JO Jump if OV = 1
Format
Description
Status word
Example
JO
Address Description
Symbolic name of jump destination.
Logic Control Instructions
If status bit OV is 1, JO 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). In a combined math instruction, check for overflow
after each separate math instruction to ensure that each intermediate result is within
the permissible range, or use instruction JOS.
BR CC 1 CC 0 OV OS OR STA RLO /FC
writes: - - - - - - - - -
STL Explanation
L MW10
L 3
*I //Multiply contents of MW10 by "3".
JO OVER //Jump if result exceeds maximum range (OV=1).
T MW10 //Program scan continues here if jump is not executed.
A M 4.0
R M 4.0
JU NEXT
OVER: AN M 4.0 //Program scan resumes here after jump to jump label OVER.
S M 4.0
NEXT: NOP 0 //Program scan resumes here after jump to jump label NEXT.
Statement List (STL) for S7-300 and S7-400 Programming
A5E00706960-01 6-11