A means is provided for separating the compressed air flowing in the instrument air path into a first path which provides actuating {TAIL ~ air} to the controllable inlet valve and {HEAD ~ the controllable depressurizing valve}, and a second path which provides a first source of signal air 
A means is provided for separating the compressed air flowing in the instrument air path into a first path which provides actuating { TAIL ~ air } to the controllable inlet valve and { HEAD ~ the controllable depressurizing valve } , and a second path which provides a first source of signal air
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH