Why would the pressure transmitters be changed from Bar(G) to Bar(A) ones? The pressure in the flow measuring system has dropped from 25 Bar(G) to 5 Bar(G). Flow is worked out using ISO 5167.
5167 uses differential pressure for flow calulation.
So the use of an absolute pressure transmitter says that a flow computer is being used to convert from volumetric flow to mass flow with temperature and static pressure compensation.
Bar G transmitters were used before the stream pressure dropped. So why now due to the lower pressure has Bar A tx's to be used? It is gas that is being measured.