In residual stress analysis (RSA) using energy dispersive (ED) diffraction care has to be taken of the detector energy stability. For a given detector system it is demonstrated that the energy position decreases significantly with dead time. Correction of the RSA data both in reflection and scanning experiments allows a significant improvement in the reliability of RSA under different conditions. Owing the small diffraction angles in ED experiments, the effect of adjustment errors in reflection geometry is investigated revealing the need of a wide incoming beam combined with high collimation of the secondary beam. The differences in the used absorber materials are shown in respect of sample heating and beam widening due to diffuse scattering.