The ATLAS Forward Proton (AFP) detectors are designed for tagging of forward protons and located inside Roman Pots (RP). My task as summer student is a data analysis to measure the distance between Silicon detectors and the RP floor. For this task there are three suggested methods: tracks pointing to the floor, slope range, and shadow of station. I tried first two methods with data from AFP run 30539. The result from tracking method is 0.7mm, however the unexpected result has to be explained to fully trust this result. In the result of the slope range method, there is an impossible result. Therefore, my code for range method needs debugging in future work