Lifo Unload (Lfu); Relay Ladder - Allen-Bradley Logix5000 Reference Manual

Chapter 9 Array (File)/Shift Instructions (BSL, BSR, FFL, FFU, LFL, LFU)

LIFO Unload (LFU)

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The LFU instruction unloads the value at .POS of the LIFO and stores 0 in that
location.
Operands:

Relay Ladder

Operand
LIFO
Destination
Control
Length
Position
If you use a user-defined structure as the data type for the LIFO or Destination
operand, use the same structure for both operands.
Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Type Format
SINT
Array tag
INT
DINT
REAL
string
structure
SINT Tag
INT
DINT
REAL
string
structure
The Destination value converts to the data type of the Destination tag. A
smaller integer converts to a larger integer by sign-extension.
CONTROL Tag
DINT Immediate
DINT Immediate
Description
LIFO to modify
Specify the first element of the LIFO
Do not use CONTROL.POS in the subscript
Value that exits the LIFO
Control structure for the operation
Typically use the same CONTROL as the
associated LFL
Maximum number of elements the LIFO can
hold at one time
Next location in the LIFO where the
instruction unloads data
Initial value is typically 0