Logix5000 Controllers General Instructions - SLAC Confluence

414 Array (File)/Shift Instructions (BSL, BSR, FFL, FFU, LFL, LFU)LIFO Unload (LFU)The LFU instruction unloads the value at .POS of the LIFO and stores0 in that location.Operands:Relay LadderOperand Type Format DescriptionLIFO SINT array tag LIFO to modifyINTDINTspecify the first element of the LIFOdo not use CONTROL.POS in the subscriptREALstringstructureDestinationSINTtagvalue that exits the LIFOINTDINTREALstringstructureThe Destination value converts to the data type of the Destination tag. Asmaller integer converts to a larger integer by sign-extension.Control CONTROL tag control structure for the operationtypically use the same CONTROL as theassociated LFLLength DINT immediate maximum number of elements the LIFO canhold at one timePosition DINT immediate next location in the LIFO where theinstruction unloads datainitial value is typically 0If you use a user-defined structure as the data type for the LIFO orDestination operand, use the same structure for both operands.Publication 1756-RM003I-EN-P - January 2007