410 Rockwell Automation Publication 1756-RM003N-EN-P - October 2011
Chapter 9 Array (File)/Shift Instructions (BSL, BSR, FFL, FFU, LFL, LFU)
FIFO Load (FFL)
The FFL instruction copies the Source value to the FIFO.
Operands:
Relay Ladder
If you use a user-defined structure as the data type for the Source or FIFO
operand, use the same structure for both operands.
Operand Type Format Description
Source SINT
INT
DINT
REAL
string
structure
Immediate
Tag
Data to be stored in the FIFO
The Source converts to the data type of the array tag. A smaller integer
converts to a larger integer by sign-extension.
FIFO SINT
INT
DINT
REAL
string
structure
Array tag FIFO to modify
Specify the first element of the FIFO
Do not use CONTROL.POS in the subscript
Control CONTROL Tag Control structure for the operation
Typically use the same CONTROL as the
associated FFU
Length DINT Immediate Maximum number of elements the FIFO can
hold at one time
Position DINT Immediate Next location in the FIFO where the
instruction loads data
Initial value is typically 0