SPIRAL2 project is based on a multi-beam superconducting LINAC designed to accelerate 5 mA deuteron beams up to 40 MeV, proton beams up to 33 MeV and 1 mA light and heavy ions (Q/A = 1/3) up to 14.5 MeV/A. The accurate tuning of the LINAC is essential for the operation of SPIRAL2 and requires measurement of the beam transverse position, the phase of the beam with respect to the radiofrequency voltage, the ellipticity of the beam and the beam energy with the help of Beam Position Monitor (BPM) system. The commissioning of the RFQ gave us the opportunity to install two BPM sensors, associated with their electronics, mounted on a test bench. The test bench is a D-plate fully equipped with a complete set of beam diagnostic equipment in order to characterize as completely as possible the beam delivered by the RFQ and to gain experience with the behavior of these diagnostics under beam operation. This paper addresses the measurements carried with the two BPMs on the Dplate: energy, transverse position and ellipticity under 750 KeV proton beam operation