Surveying assignment
- 1. SURVEYING ASSIGNMENT TOPIC: DIGITAL LEVEL AUTO LEVEL SUBMITTED BY ZUBDA SAJDA BARCH/15047/14 BIT PATNA
- 2. DIGITAL LEVELS This is the latest form of the level, which can eliminates the need to read the staff and record readings. It is also known as Electronic level. It is very powerful and accurate for many uses. Both electronic and optical readings are possible. Digital levels are used for all types of leveling operations in precise level and in tachometry. It uses a compensator mechanism, it is helpful to take care of small tilt in the axis. .
- 3. COMPENSATOR •It consists of two mirrors or prisms, fixed to the barrel of the telescope. •Another prism or mirror is suspended by two non-magnetic wires and moves by the action of gravity when the telescope is tilted. •A ray of light gets reflected from the fixed and suspended mirror or prisms and always remains horizontal. •A damping device with counter weight is provided to prevent excessive oscillations of the system.
- 4. •The mechanism also consists of a circular bubble, this is required to activate the compensator when the telescope is not perfectly level. Fig: a)components of digital level instrument b)Compensator mechanism (a) (b)
- 5. Digital levels are used in conjunction with a special bar coded staff. Software is built into the level to read the staff and send information to the digital display unit. Once the bar-coded staff is sighted, a button is pressed to take the reading. The reading is taken, stored and displayed on a console screen in a matter of seconds. The built in software programs enable distances and elevations to be calculated and displayed.
- 6. The instrument can be powered by normal batteries or rechargeable battery pack with a working time of 10 hours. The level is useful in topographic surveys, tunnel surveys and mine surveying. Examples of digital level: DL 100 Digital Level Sokkia’s SDL 30 Digital Level Other facilities can also be added by the manufacturer. The data which is obtained can also be fed to a computer through an RS-232 cable for future processing.
- 7. The operating functions and software of digital level include following :- Horizontal distance measurement to staff for contouring. Height determination of intermediate points. Calculation of difference in elevation. Selectable minimum unit for reading. Alphanumeric input of function.
- 8. AUTOMATIC (auto) LEVEL The automatic level is very easy to operate. It ensures accurate leveling. It is simpler and convenient to use . Typical parts of an auto level The auto level has the following components in three different views: 1.Right side view The leveling head is a very important component in this view. It has three parts a. A circular plate, or tribrach, which carries a spirit level and the instrument . b. Three leveling screws or foot screws. c. A foot plate or trivet attached to the tripod head .
- 9. 2.Top view The view shows the following parts: •Spherical level, practically a sprit level where the bubble must be within the circle to give a horizontal line of sight. •The instrument can be rotated by hand using “gun sight” at the telescope. •The object focusing screw to focus the staff or other object image properly . • Tangent screw on each side help in finer adjustment for focusing the image of the object.
- 10. 3.Left-side view A mirror fitted over the spherical level is the only new component in this view. In an automatic level, the line of sight is automatically made perpendicular to the vertical axis by an optical system called compensator. A compensator is an optical unit consisting of prisms placed in the optical path between the eye piece and the objective. It consists of two mirrors or prisms, fixed to the barrel of the telescope.
- 11. Fig: auto levels a)Mechanism of compensator b)Components of auto level instrument c)A typical auto level instrument (a) (b) (c)
- 12. Another prism or mirror is suspended by two non- magnetic wires and moves by the action of gravity when the telescope is tilted. A ray of light gets reflected from the fixed and suspended mirror or prisms and always remains horizontal. A damping device with counter weight is provided to prevent excessive oscillations of the system. The mechanism also consists of a circular bubble, this is required to activate the compensator when the telescope is not perfectly level.
- 13. The automatic level is vey easy to operate. Once the telescope is approximately level, the compensator is active and we have to take readings on the staff by keeping it at different points. The adjustment of the compensator is a highly specialized job and should be got done from the manufacturer. The compensator are generally quite robust, and they rarely go out of adjustment. Example of automatic level: NI-NA 20 Automatic level The instrument is fully scaled and can be used even in rain, dust, snow, cold or heat.
- 14. Advantages of auto level:- •It is much simpler and convenient to use. •The leveling work is done quickly and economically. •It gives an erect image. Therefore, the staff reading is taken easily. •There is no error due to inaccurate centering of the bubble.
- 15. REFERENCE:- TEXTBOOK 1.SURVEYING (VOLUME-II) BY DR. K.R ARORA 2. FUNDAMENTALS OF SURVEYING AND LEVELLING BY R. SUBRAMANIAM
- 16. THANK YOU