Installation manual

Publication 1747-RM001G-EN-P - November 2008
6-2 Program Flow Instructions
Jump to Label (JMP) and
Label (LBL)
Use these instructions in pairs to skip portions of the ladder program.
Jumping forward to a label saves program scan time by omitting a program
segment until needed. Jumping backward lets the controller execute program
segments repeatedly.
Entering Parameters
Enter a decimal label number from 0 to 255 in each subroutine file.
Using JMP
The JMP instruction causes the controller to skip rungs. You can jump to the
same label from one or more JMP instructions.
(JMP)
]LBL[
Fixed SLC
5/01
SLC
5/02
SLC
5/03
SLC
5/04
SLC
5/05
• •••••
Table 6.2 Program Function
If the Rung
Containing the
Jump Instruction
is
Then the Program
True Skips from the rung containing the JMP instruction to the rung
containing the designated LBL instruction and continues executing.
You can jump forward or backward.
False Does not execute the JMP instruction.
TIP
Be careful not to jump backwards an excessive
number of times. The watchdog timer could time out
and fault the controller. Use a counter, timer, or the
program scan register (system status register, word
S:3, bits 0 to 7) to limit the amount of time you spend
looping inside of JMP/LBL instructions.