In one of the long straight sections of SOLEIL is installed a pair of canted undulators for the ANATOMIX and NANOSCOPIUM beamlines. Since the upstream undulator radiation can potentially damage the downstram undulator magnets, an accurate survey of the respective alignement of the two devices is mandatory. An XBPM was initially installed for this purpose. But for redundance and further analysis, an X-ray analysis was then installed just downstream the XBPM. We present the commissioning of this new device together with its first results in operation.