A method for reading out a sensor unit having a first set of nodes and a second set of nodes and a symmetry which allows different configurations of excitation and sensing lead to a same readout. The method includes changing the readout configuration of the sensor unit by exchanging excitation and sensing between the first set of nodes and the second set of nodes, evaluating the similarity or deviation between measurement signals obtained in different readout configurations of the sensor unit, raising an error if the measurement signals differ more from one another than a predetermined value.