... follows:1. Start up the instrument, and vertical angle crosses zero.2. Press key and key simultaneously, and the instrument will ... row. Repeatedly press it display Ua, Ub and Uc by turn. 6. Press key twice to change the number 30 in ... row. Repeatedly press it display 0, 20 and 30 by turn. 7. Press key, and the TILT will disappear and the ...