Hello, I am working on modifying a Fusion post for my Hyundai lathe by starting with a Doosan/Fanuc post which seems to be close. I'm now stuck on trying to figure out what M91 is used for on a Doosan. My machine doesn't like the code, some I'm trying to find it and delete from my post with no luck so far. All I can find so far is it's used as an extra M code specific to the machine. Thanks in advance, Dan