When using a basic differential pressure transmitter for flow measurement, what varies with the flow?

When using a basic differential pressure transmitter for flow measurement, the output signal varies with the flow. This is because the differential pressure transmitter is designed to measure the difference in pressure between two points. In the case of flow measurement, the pressure differential is created by the restriction in the flow path, such as an orifice plate.

As the flow rate increases, the velocity of the fluid passing through the restriction also increases, which in turn affects the pressure drop across the orifice. The transmitter senses these changes in pressure and converts them into an electrical signal or output signal that is proportional to the differential pressure. Therefore, as the flow changes, the output signal from the transmitter will also change, allowing for accurate flow measurement.

Understanding this relationship is crucial for effectively using differential pressure transmitters in flow applications, as it directly ties the mechanical flow concept to the electronic representation that the transmitter provides.