That's the problem: there is no unsigned integer format in the SLC-500 controllers.
The MicroLogix 1100/1200/1400/1500 have a Long Integer format, which would display a 16-bit unsigned integer correctly.
Otherwise your principal option is to convert the value to Floating Point, with some possible loss of precision (though with a 16-bit value, not much).
You'll have to do a little bitwise manipulation to do this: use a Masked Move to remove the sign bit, then add +32768.0 to the resulting value if the sign bit (the highest bit, /15) is true.