This sounds pretty good. You might try saying "various digital I/O modules" instead of "different."there are different digital IO modules and each has a different operating voltage range.
It seems that if you have to state it more clearly separately so we understand what you mean, the original sentence should just be replaced by the clarified sentence, i.e.:Does this sentence make sense and is there a better way to say it?
"Digital I/O modules have a variety of operating voltage range. "
what i'm trying to say is that there are different digital IO modules and each has a different operating voltage range rating.