... X axle£» press CAL button until 3 munites ,on screen can be display:standard type DX,length=**mm;through SEL,,button to ... to calibration length,and press CAL button,on the left screen can show the calibration OK,then into Y axle calibration ... the 2 parallel lines survey distance.Attention:under surveying don't change the enlargement factor,if changed,should be take a ...