Study of impurity behaviour for first magnetic configuration changes in W7-X plasmas by means of PHA spectra

•The effect of planar coil current changes on the core impurity behavior in the first operating phase of W7-X is presented.•Hydrogen plasmas, at different heating power levels were investigated showing CERC conditions.•The He-, and H-like Sulphur, Chlorine and Argon lines in the x-ray emission range between 1 and 10 keV were measured by the PHA diagnostic.•The scans of the magnetic configuration did not affect the impurity concentration.•Differences in the impurity content have been observed when the ECRH power was changed.