Use this page of the Properties dialog box to specify the size of an array.
(FPGA Module)Adapt to source—Sets whether the array size and dimension adapt to the input values wired to the function. This checkbox appears only in an FPGA VI under an FPGA target.
Dimension(s)—Number of dimensions in the array.
(FPGA Module)Array Size—Sets the size of the array. This option is available only in an FPGA VI under an FPGA target.