Method for commissioning a magnetic inductive flowmeter, and a magnetic inductive flowmeter

A method for determining a flow velocity and/or a volume flow of a conductive liquid medium, comprising:

• providing a magneto-inductive flow measuring device, including:
• a means for producing a magnetic field;
• an operating unit including a means for applying an electrical voltage to the means for producing the magnetic field to produce the magnetic field;
• and
• a measuring electrode pair for sensing a potential difference in a medium;
• applying a first voltage time function to the means for producing the magnetic field, wherein the first voltage time function is applied for a settling time ta that is divided into settling time intervals ta,i, wherein the first voltage time function changes sign after each settling time interval ta,i, and wherein the first voltage time function is applied until an end value of the magnetic field differs from a desired value of a steady-state magnetic field by less than 0.25% according to the following inequality:
• ❘
• "\[LeftBracketingBar]"
• B
• actual
• -
• B
• desired
• B
• desired
• ❘
• "\[RightBracketingBar]"
• <
• Δ
• ,
• wherein Δ is 0.25%, Bactual is the magnetic field end value, and Bdesired is the desired value of the steady-state magnetic field;
• applying a second voltage time function to the means for producing the magnetic field, wherein the second voltage time function is applied for a measuring time tm that follows the settling time ta and that is divided into measuring time intervals tm,j, and wherein the second voltage time function changes sign after each measuring time interval tm,j;
• measuring, during the measuring time tm, a potential difference across the measuring electrodes;
• and
• calculating, during the measuring time tm, the flow velocity and/or the volume flow of the conductive liquid medium based on the measured potential difference across the measuring electrodes.