Not an easy thing
Not an easy thing
What you are asking for is not an easy thing, allot has to do with knowing the machine. First thing TURN OFF POWER; Don't let anyone at work talk you into trying it with power on. Break it down into two groups Power and Control, mark everything temporary first so if you find something you missed it don't take much to fix. My approach was to take one conduit at a time and trace from there, branching out when needed. It takes allot of time but it can be done.
Also make a note on prints that this was a traced circuit and may have missed something, nothing worse than finding out something is not on prints.
Good Luck and after you draw the prints you WILL know the machine inside and out.