How Is Flow Rate Calculated?
2019-06-12
In the digital domain, the ac flow signal will still need filtering and synchronous demodulation.
The picture illustrates how the algorithm implements the synchronous demodulation in the digital domain.
A DSP issues Control Signal 1 and 2, a pair of complementary logic signals for the electromagnetic flow sensor coil excitation. Under the control of these two signals, the current flowing through the electromagnetic flow sensor coil re-verses in each cycle—thus the direction of the magnetic field and therefore the sensor output on the electrodes.