On the M400 you can select ref sync rise or falling edges,is this possible on the M4? I've scoped the ref and sync and to keep the two as far away as possible I think I need rise and rise.
Indeed you can set the ref/sync mode to rise/rise in the M4. Under the general setup, main menu, you can set the ref/sync mode to 11 and it will be rise/rise. I know because I've had to do this myself.