Are you trying to be clear and obvious so anyone can find any machine? Systems like the DC-1234-RD? If so, I suggest two things:
1. Sequence of characters should be from general to specific. Like Site# - Tag#, as suggested first. That way when all names are sorted, it will make more sense and be easier to find one machine.
2. Don't bother with hyphens etc in the sequence. They are meaningless for any classification system, and useful only for people reading. Just as useful is a rigidly-defined format like AAAnnnn where AAA must be exactly three alphabetic characters, and nnnn must be 4 digits. Remember the old rule the phone companies discovered decades ago: people can remember character / number sequences of up to 7 characters, but have trouble beyond that. That is why we have phone numbers in North America like 987-6543.
Or, are you trying to be as non-structured as possible to keep prying people away? A collection of names with no rules at all makes it harder for an outsider to poke around, I suppose, but I doubt that would hamper a good hacker. But if that is your idea, make only VERY loose guidelines (e.g. no names of wives, dogs and kids) and then let each user create their own name. Hundreds of people are more randomly creative than two IT techs.