Firstly turbine flowmeter converts the flow rate to the speed of the turbine and then the speed converts into an electrical signal that is proportional to the flow rate. This flow meter is used to detect instantaneous flow and total flow. The output signal is frequency and it is easy to digitize.
There is sensing signal detected when ferromagnetic turbine blade passes the magnet, the resistance of magnetic is changing. The signal is amplified and shaped by an amplifier sent to a counter or frequency meter to show the total integrated flow. At the same time, the pulse frequency goes through frequency-voltage converted to indicate instantaneous flow. The speed of the impeller is proportional to the flow rate, and the number of revolutions of the impeller is proportional to the total amount of flow.
The output of the turbine flowmeter is a frequency-modulated signal, which not only improves the immunity of the detection circuit, but also simplifies the flow detection system. Its range ratio is up to 10:1 and its accuracy is within ±0.2%. The time constant of the small inertia and small size turbine flowmeter can reach 0.01 second.