Method for start-up of a measuring device

1. A method for start-up of a measuring device, which is embodied to monitor by means of at least one measuring transducer in contact with the interior of a process container, a measured variable of a medium contained in the process container, wherein, for ascertaining a measured value, at least one measurement signal of the measuring transducer is mapped to a measured value of the measured variable according to a predetermined characteristic curve, wherein the method comprises the steps of:

introducing a process medium into the process container;

bringing the measuring transducer in contact with the process medium; and

performing a one-point calibrating of the measuring device based on a measurement signal registered by the measuring transducer in the process medium or a measured value derived therefrom based on the characteristic curve, wherein:

the process medium is a feeding medium for microorganisms of a biotechnological process, whose value of the measured variable to be monitored by the measuring transducer is known.

2. The method as claimed in claim 1 , wherein:

said one-point calibrating includes the steps of:

registering by means of the measuring device a measured value of the measured variable of the process medium as a current calibration measured value; and

updating the predetermined characteristic curve (according to which a measurement signal of the measuring transducer is mapped to a measured value) stored in a memory associated with the measuring device based on the current calibration measured value.

3. The method as claimed in claim 1 , wherein:

the characteristic curve is a straight line; and

the straight line is corrected based on the current calibration measured value of the zero-point (axial intercept).

4. The method as claimed in claim 1 , wherein:

the process medium is a feeding medium for microorganisms of a biotechnological process, whose chemical composition is known.

5. The method as claimed in claim 1 , wherein:

the measured variable is one of a pH-value, conductivity, or a concentration of a substance.

6. The method as claimed in claim 5 , wherein:

said concentration of a substance is one of: a concentration of a dissolved gas or of a type of ion or a concentration of a substance relevant for a biotechnological process to be monitored.

7. The method as claimed in claim 1 , wherein:

the process container is one of:

a single-use container, a bag-fermenter, a hose, or a tubular connection, for application in a biotechnological process.

8. The method as claimed in claim 1 , wherein:

the measuring transducer is a potentiometric sensor with a measuring half cell and a reference half-cell;

the sensor has an immersion region, which includes a membrane of a said measuring half cell sensitive for the measured variable to be monitored and an electrolytic contact location for providing electrolytic contact between the reference half-cell and the process medium; and

the measuring transducer is brought in contact with the process medium by immersing the immersion region in the process medium.

9. The method as claimed in claim 1 , wherein:

the measuring transducer is an optical sensor with a light source and a receiver, which outputs a measurement signal dependent on a light intensity received by the receiver; and

the optical sensor is brought in contact with the process medium by radiating light emitted by the light source on a light path extending between the light source and the receiver through the process medium.

10. The method as claimed in claim 9 , wherein:

the light is emitted by the light source on a light path extending between the light source and the receiver through the process medium and a wall of the process container.

11. The method as claimed in claim 1 , wherein:

supplementally taken into consideration in the one-point-calibration are matrix effects, which result through cross sensitivities of the measured variable to be monitored to other measured variables.