US Patent 7287434 System and method for measuring flow

One embodiment of the present invention can comprise a primary flow measurement system, a secondary flow measurement system in fluid communication with the primary flow measurement system and a control coupled to the primary flow measurement system and the secondary flow measurement system. The controller can comprise a processor and a memory accessible by the processor. The processor can execute computer instructions stored on the memory to calculate a flow rate using the primary flow measurement system, in a first mode of operation, and calculate the flow rate using the secondary flow measurement system, in a second mode of operation. The computer instructions can be further executable to switch between the first mode of operation and the second mode of operation based on a predefined parameter.