Calibration is something that everyone who works with test equipment is familiar with. A calibration procedure involves comparing an equipment’s settings to those of a standard in order to obtain accurate measurements. The auto level is just one of the many survey instruments that require regular maintenance and calibration. A step-by-step guide on how to calibrate an auto level is provided below. If you want to do it yourself, this guide will assist you in the calibration of your auto levelling system.
1. Remove the top, bottom, left, and right screws from the auto level’s cover to reveal the inside. The top and bottom screws are the only ones that need to be adjusted if you only want to collimate (adjust accurately the line of sight) an auto level.
2. Set the auto level in the centre of two staffs (each of approximately 60m in length) and take the readings for backsight (BS)-point A and foresight (FS)-point B using the auto level. Before you begin reading, double-check that the instrument is properly levelled. This difference between BS and FS that you obtain as a result of this procedure is obtained without collimation, and the reading should be used as a benchmark for adjustment.
3. Shift the auto level to point D which is L/10 (L is the length of point A to point B).
4. Take a look at the nearest staff and make a note of the value. This value should be added to the difference between BS and FS that you obtained in step 2.
5. Now, using the screw, loosen and tighten the bottom and top screws respectively. To get the “Actual value,” adjust slowly. If the top screw becomes loose, tighten the bottom screw until the top screw is tight. As a result, your calibration is complete, and you will receive either the perfect value or a value that differs by one millimetre.
6. After you’ve completed your auto level calibration, you can retrieve the alignment. Return to the intersection of points A and B. Check the reading one more time. You should be able to get the perfect reading now.
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