No Operation (Nop); Relay Ladder - Allen-Bradley Logix5000 Reference Manual

Program Control Instructions (JMP, LBL, JSR, RET, SBR, JXR, TND, MCR, UID, UIE, AFI, NOP, EOT, SFP, SFR, EVENT)

No Operation (NOP)

Description:
Arithmetic Status Flags:
Fault Conditions:
Condition
Prescan
Rung-condition-in is false
Rung-condition-in is true
Postscan
The NOP instruction functions as a placeholder.
Operands:

Relay Ladder

None
You can place the NOP instruction anywhere on a rung. When enabled the NOP
instruction performs no operation. When disabled, the NOP instruction
performs no operation.
Not affected
None
Execution:
Relay Ladder Action
The rung-condition-out is set to false.
The rung-condition-out is set to false.
The rung-condition-out is set to true.
The rung-condition-out is set to false.
Example
This instruction is useful for locating unconditional branches when you place the
NOP instruction on the branch.
The NOP instruction bypasses the XIC instruction to enable the output.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 11
473