Calibration procedure of ∆ E - E detectors used in dp breakup reaction measurement in the framework of DSS project is discussed. Time information from all PMTs along with amplitude information and known energy values of pp quasi elastic reaction are used to find calibration coefficients for ∆ E and E detectors. Calibration coefficients are used to recover deposited particle energies. ∆ E vs. E plots, energies and missing mass spectra are compared with geant4 Monte Carlo simulation. Missing mass for particular physical configuration is calculated as a test of the calibration procedure quality.