The paper presents the physical aspects of the procedure of the preparation of the device and the cross-sample calibration. The innovative MAgStressACS automatic calibration machine is used to carry out the process. This device is an effective solution for quickly generating calibration curves of the dependence of Barkhausen effect on strain in biaxial stress state. A cross-sample for calibration is made of S355 steel. This sample is used in all further tests. During the calibration process, 50 measurement points are assumed. Based on the experimentally performed tests, calibration curves and two-dimensional calibration maps are determined. The obtained results constitute a basis for reference results for further research on the stress state and deformations of the real steel constructions.