Rockwell Automation Publication 1756-RM003N-EN-P - October 2011 465
Program Control Instructions (JMP, LBL, JSR, RET, SBR, JXR, TND, MCR, UID, UIE, AFI, NOP, EOT, SFP, SFR, EVENT) Chapter 11
Temporary End (TND)
The TND instruction acts as a boundary.
Operands:
Relay Ladder Operands
None
Structured Text
None
You must enter the parentheses () after the instruction mnemonic, even though
there are no operands.
Description: When enabled, the TND instruction lets the controller execute logic only up to
this instruction.
When enabled, the TND instruction acts as the end of the routine. When the
controller scans a TND instruction, the controller moves to the end of the
current routine. If the TND instruction is in a subroutine, control returns to the
calling routine. If the TND instruction is in a main routine, control returns to the
next program within the current task.
Arithmetic Status Flags: Not affected
Fault Conditions: None
Execution:
Condition Relay Ladder Action Structured Text Action
Prescan The rung-condition-out is set to false. No action taken.
Rung-condition-in is false The rung-condition-out is set to false. N/A
Rung-condition-in is true The instruction executes.
The rung-condition-out is set to true.
N/A
EnableIn is set N/A EnableIn is always set.
The instruction executes.
Instruction execution The current routine terminates. The current routine terminates.
Postscan The rung-condition-out is set to false. No action taken.
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