I am using the sdk version : PS3000asdk_r10_5_0_29 and i think i define an application buffer with this function: invoke(ps3206B_obj, 'ps3000aSetDataBuffer', ... Channel_A, ... dataChA.pBufferNoneA, ... MaxBufferSizeChA, ... SegmentIndex, ... enuminfo.enPS3000ARatioMode.PS3000A_RATIO_MODE_NONE); If ...