def dscan(self, motor, start, finish, npts, dtime):
        self._checkmotors(motor)
        current = self.motors[motor].current()
        start  += current
        finish += current
        self.ascan(motor, start, finish, npts, dtime)
dscan: relative scan
dataset/ETHPy150Open xraypy/xraylarch/plugins/epics/spyk.py/Spyk.dscan