A method for operating a measuring instrument is capable of performing multiple diagnostic functions. For this, a process control is provided for the execution of the diagnostic functions in a manner whereby the normal measuring operation of the measuring instrument is interrupted, a first diagnostic function is performed during that interruption, the normal measuring operation is resumed after completion of the first diagnostic function, the normal measuring operation is again interrupted, and during that later interruption of the normal measuring operation a second diagnostic function is performed. In this fashion, even numerous diagnostic functions can be easily and efficiently integrated into the operation of a measuring instrument such as a magnetoinductive flowmeter.