Straton Calling UDFB in STL

Dear all,

I am trying to convert 2 words to real (IEEE754 Floating point Value)

i already have the UDINT Value by using

var_udint := shl(any_to_udint(HighWord), 16) + any_to_udint(LowWord))

but using,

var_real := any_to_real(shl(any_to_udint(HighWord), 16) + any_to_udint(LowWord)))

this conversion is not converting to floating point IEEE754

so i tried to create the manual calculation using UDFB, but currently i don't know how to call the UDFB.

There is this error when i am trying to build the project. Can somebody show me how to call the UDFB? and could this UDFB called many times in other variable?

Thanks for your attention.

Error When Calling the UDFB

IEEE754 Conversion