people who are seriously involed in pneumatics acctually use those diagrahms... the fact that they put it the other way round is exactly as if they wrote it's a NO valve but put it in the right way in the diagrahm
I've found something on it on exactly the same page
so you see... someone might have already ordered or will order a wrong valve becasue of this mistakeNational Fluid Power Association (NFPA) Diagrams— Found on most air control valves, these diagrams depict air flow and valve action. They're useful for replacing control valves—match the diagram on your valve to the new valve.
that was just to clear things up