The fact below is a description of what a theodolite is.
Very often in various fields of activity there is a need to measure angles. The usual stationery protractor here will look ridiculous. Therefore, there is a special device with the interesting name "theodolite". This is a measuring device, which is used in geodetic or topographic surveys and just at a construction site, used to measure horizontal and vertical angles. Measurements take place with the help of a string range finder or compass.
A theodolite is a device designed to measure horizontal and vertical angles.
Theodolite: the principle of action
Theodolite appeared in the 17th century. Then he combined in himself two useful devices: a device for measuring angles and a telescope. Today's modern theodolites are just as popular. They are used in geodesy and during the construction of industrial buildings, where not only the production but also the safety of people depends on the accuracy of the location of the installations.
The very first theodolites had the following construction:
- the instrument had a goniometer circle, its other name was “limb”, in the center of which there was an arrow rotating on a needle, like a compass needle;
- on the ruler there were cutouts, equipped with threads, with the help of which the calculation was carried out;
- the angular circle was attached to the top of the angle required for measurements;
- turning, it was necessary to combine the angle with any thread, it was the first mark;
- by the same principle, the second mark was noted;
- the difference is equal to the angle value.
Modern theodolites do not differ in design and principle of operation, with the only difference that there has been a significant improvement in design.Back to table of contents
Classification of modern theodolites
Theodolites can vary significantly. It depends on their distinctive features. Let us consider in more detail the classification of this tool.
Varieties of theodolites:
For proper operation, the theodolite must be firmly mounted on a tripod.
- If we consider the accuracy, the tools are divided into accurate, technical and high-precision. The standard deviation of such tools is up to 15, more than 20 and up to 1 second, respectively.
- Theodolites are distinguished by their design. So, distinguish between simple and repetitive theodolites. In the simple form of the instrument, the arrow is securely fastened to the vertical axis, while in the case of repetitive limbs with an arrow they rotate jointly and separately. Separate rotation and makes it possible to measure the angle by repeating.
- Simple theodolites are divided into photo films and also gyrotheodolites. According to their structure, they are intended for use in certain areas.
- Today, electronic theodolites are mainly used. This type of measuring device has a special device that measures the coordinates of points, due to which the calculations take place. In addition, this measuring device allows you to work at night.
Modern theodolites - which ones are better?
To date, produce two types of this tool: optical and electronic. It is impossible to say which one is better. Each has its pros and cons.
Optical theodolite differs only in that it requires preparation for work. It must be properly installed using a cylindrical level, observing the exact horizontal position. It has three screws for lifting. They must be properly adjusted to bring the instrument into working condition. In addition, an optical theodolite has a telescope, which is necessary for conducting observations.
Types of verification of theodolite: a - installation by two screws; b - installation on the third screw; in - checking the correctness of the installation level.
Electronic theodolite makes measurements automatically. Having a liquid crystal display, it accurately determines the value and displays it on the screen. That's just such devices do not remember the values. They need to be used only where there is electricity, since the electric tool has no batteries. In other cases, also used an optical device.
Instructions for use are for each device of any model, so using it will not cause any problems.
As a result, we can conclude that the choice of a tool directly depends on the person to be used. He must decide on the financial costs, convenience and characteristics of the device.
Each model of theodolite has its own technical characteristics. They differ significantly in features such as lighting, field of view, prices, scale division, errors, etc.
We list the main characteristics that apply to most varieties of the measuring tool:
- theodolite mass with stand average from 4 to 5 kg;
- operating temperature of the device -40 - +50 degrees Celsius;
- the average error of the device is 0.1 ”;
- scale division price - 1 ";
- warranty from the manufacturer - 3 years.
Before purchasing a theodolite, you should carefully study the specifications and issue a guarantee.Back to table of contents
Instructions for theodolite
The use of any device must be carried out strictly according to the instructions, which contains guidance on the application.
The instruction contains the stated security measures directed more at the correct use of the measuring device, on realization of the correct measurements.
The scheme of measurement of vertical angles by theodolite.
- Measurement of the horizontal angle. Before starting the measurement, install the theodolite in the correct working position. Depending on the variety and model, various leveling and centering are carried out to achieve the most accurate and correct indicator. Further, setting the axis of rotation at the top of the working measured angle, they are taken for fixing the indicators. When the circle "left" guide the pipe to the first side of the angle and fix its value. Then, turning clockwise, the pipe reaches the second side, where the mark is also fixed. Calculate the difference, the value is memorized. The same procedure is carried out with the circle "right". Calculate the angle value. To accurately determine the value of the measured angle, we take the arithmetic average of two quantities.
- Measurement of the vertical angle. It uses a vertical circle, where the center of the limb and the geometric axis are combined. In this case, the limb must be securely fixed at one end of the axis. As with the measurement of the horizontal angle, set theodolite in working condition, depending on the model and type. Next, you should determine the place of zero, and then count the top circle in two steps. Values in the techniques of "right", "left" are calculated and remembered. The arithmetic average will be the final value of the measured angle.
Electronic and optical theodolite should be used only for its intended purpose. The contents of the manual must be observed during operation. By purchasing a theodolite in a specialized store, you automatically get the possibility of warranty service. Therefore, in case of malfunctions, you should immediately seek help from a specialist. Otherwise, you can take the device completely out of working condition.