How do I read/write 32 bit words from 16 bit registers?

How do I read/write 32 bit words from 16 bit registers?

All of the Hardy units have the posibility of sending 20 or 32 bit data to a PLC using 16 bit integer locations. 

Attached is a document explaining the two word weight readings that will let you better understand how they work. This document refers to 20 bit words, but the concept is the same for 32 bit words. The actual combining two words in the Rockwell PLC would be a Rockwell support question.