FSV430:  Vortex flowmeter for vapor, liquid and gas, with optional graphical display, optional binary output and optional integrated temperature measurement.

FSV450:  Vortex flowmeter for vapor, liquid and gas, with integrated binary output, temperature compensation, and flow computer functionality. The device offers the option of directly connecting external temperature transmitters, pressure transmitters or gas analyzers. 

Measuring principle :The operating principle of the Vortex flowmeter is based on the Karman street. As the fluid flows over and under the solid body, vortices are shed alternately above and below. The shedding of these vortices due to the flow forms a vortex trail (Karman street).