Pipetting apparatus for aspirating and dispensing liquids

A method for operating a pipetting apparatus having a pipetting unit with an interchangeable vessel that receives a liquid to be transferred, a holder for the pipetting unit having a movable contact device with at least one contact element, a positioning device for the pipetting unit, a micrometering unit having a counterpart contact device with at least one counterpart contact element, and an electronic control device, wherein the micrometering unit is embodied separately from the pipetting unit and has a separate electronic control unit,

• the method comprisomg at least the following method steps:
• a) moving the holder, by means of the positioning device, from an end position on the micrometering unit into a starting position of a coupling operation, in which the contact device and the counterpart contact device are spatially at a distance from one another,
• b) moving the holder further by means of the positioning device into an intermediate position, in which the contact device is substantially one-dimensionally spaced apart from the counterpart contact device, such that the at least one contact element and the at least one counterpart contact element are spaced apart from one another,
• c) moving the holder further by means of the positioning device into a contact position in which the at least one contact element and the at least one counterpart contact element produce an electrical connection, and
• d) to release the electrical connection, moving the holder by means of the positioning device into an end position at a distance from the micrometering unit, wherein the method steps c), b), a) are executed in that order.