Statement List (STL) - DCE FEL ČVUT v Praze

6.18 JUO Jump if Unordered
Format
Description
Status word
Example
JUO
Address Description
Symbolic name of jump destination.
Logic Control Instructions
If status bits CC 1 = 1 and CC 0 = 1, JUO 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).
Status bits CC 1 = 1 and CC 0 = 1 when
• A division by zero occurred
• An illegal instruction was used
• The result of a floating-point comparison is "unordered," that is, when a invalid
format was used.
BR CC 1 CC 0 OV OS OR STA RLO /FC
writes: - - - - - - - - -
STL Explanation
L MD10
L ID2
/D //Divide contents of MD10 by contents of ID2.
JUO ERRO //Jump if division by zero (that is, ID2 = 0).
T MD14 //Program scan continues here if jump is not executed.
A M 4.0
R M 4.0
JU NEXT
ERRO: AN M 4.0 //Program scan resumes here after jump to jump label ERRO.
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 6-19