A method of operating a flowmeter and flowmeter

Described and illustrated is a method (1) for operating a flow meter (2) for performing a plurality of temporary measuring processes, wherein the flow meter (2) at least one diagnostic unit (3), a counter unit (4) and a memory unit (5) having at least a memory (6), wherein the counter unit (4) is at least by the flowmeter during a measuring process (2) is determined passing total volume of a fluid, and wherein the counter unit (4) is operated for the duration of a temporary measuring process, wherein the diagnosis unit (3) detects an erroneous or error-free state of the flowmeter at least. The object to provide a method of operating a flowmeter that guarantees a particularly high reliability of the determined during individual measuring processes measured values ​​is achieved in that the diagnostic unit (3) generated based on the state of at least a status message (9) and the status message (to the memory unit 5) transmitted, and in the memory (6) of the storage unit (5) is stored, and that if a plurality of status messages (9a) is transmitted, this cumulative (at least for the duration of the measurement process in the memory 6) of the storage unit (5) are stored.