What is a hydraulic machine? Errors are common when using a leveling machine

Even though when shipped, the machine has been tested and calibrated, but in reality, errors can still occur. The cause may come from measurement operations, the user's way of reading numbers or the impact of the external environment. So where exactly do these errors come from? Join us to find out details in the article below!

So what is a hydraulic machine?

Automatic Level helps determine relative heights between points in space. If you work in the field of construction, cadastral or infrastructure design, you have certainly heard of it. It can be said that this is an indispensable tool for creating accurate horizontal planes, supporting construction and checking building heights.  

When using a thermos, a mic is a must-have accessory. Imagine the mia as a special ruler, with clearly engraved lines to help you read measurement results easily. Depending on needs, the diaphragm can be from 2 to 5 meters long, ensuring flexible measurement in many different terrains.  

Choosing the right dia for each type of water tank is not easy. Compatibility between equipment and accessories helps make measurements more accurate and minimize errors, helping work go quickly and efficiently. 

Some common errors when measuring level machines  

The following are common errors when using a leveling machine:

Error due to the machine's vertical axis being tilted  

Cause: The axis of the water tube is not parallel to the rotation axis of the machine, especially with devices with automatic balancing mechanisms, the vertical axis is not allowed to tilt when rotating the lens. If the machine axis is tilted, the readings on the front and rear wheels will no longer be accurate.  

Solution: Before measuring, it is necessary to test and calibrate the machine to ensure that the water bubble is in the middle position. When working, you should measure again and again to minimize errors and check the error of angle i accurately. 

Error due to the machine sinking 

Cause: The terrain has weak, unstable ground.  

Solution: The machine will sink over time standing in one position, so it is necessary to operate quickly and choose the appropriate measurement method to limit errors.  

Error due to needle subsidence  

Cause: The ground is unstable, leading to a change in the position of the needle when measuring.  

Solution: Use a diaphragm support base to limit the influence of soft ground, read numbers quickly and measure back and forth to get the average value, ensuring more accurate results. 

Error due to uneven dm divisions on the diaphragm  

Cause: The terrain is not absolutely flat, the height of the leveling machine changes with each measuring point, leading to errors when reading numbers on the screen.  

Solution: Balance the machine carefully, adjust so that the machine height does not change too suddenly according to the terrain.  

Error due to image vibration in the air layer close to the ground 

Cause: Near the ground, air density decreases with altitude, causing vertical refraction. This causes the image to shake, especially when the aiming beam is low.  

Measures: Avoid taking measurements when the sun is hot or the temperature is too high. If possible, raise the machine height to reduce the effects of this phenomenon.

Error due to tilted diaphragm

Cause: The diaphragm does not have a round bubble or does have one but is not accurate, leading to the axis of the diaphragm not being parallel to the vertical axis of the diaphragm, causing errors when measuring.  

Measures: Regularly check data to ensure accuracy and avoid data discrepancies. 

Errors due to curved diaphragms, the difference in points of each pair of diaphragms, and the average length of 1m on the diaphragms

Mia may warp over time due to environmental factors or material deterioration. This directly affects the measurement results.

Solution: Periodically check to ensure the needle is not deformed and maintains measurement accuracy.

Error due to the prism of the leveling machine  

This error occurs when the optical prism on the optical axis does not ensure accuracy, causing misfocus.  

Measure: When measuring, make sure the distance from the two needles to the leveling machine is equal. This helps reduce focal shift and minimize errors.  

Error due to lens separation ability  

The separation ability of the lens determines the sharpness when reading the numbers on the screen. If the lens has low resolution, the reading will easily be misleading.  

Solution: Choose a leveling machine with good lens quality, making images sharper and reducing errors when reading data.

Error due to rounding of readings 

Mia has very small engraved lines, when reading numbers, you usually have to round to 0.1 units. This error is influenced by many factors such as: the eye's ability to separate, brightness, thickness of the number line, transparency of the environment,...  

Solution: This error is difficult to completely avoid but can be reduced by carefully checking when reading numbers, ensuring good lighting and choosing a machine with high resolution.

Error due to the influence of the Earth's curvature

The Earth is not an absolutely flat surface, but has a slight curvature, which leads to errors when measuring long distances.  

Solution: Always place the device in a central position, equidistant from each other to limit the impact of the Earth's curvature..  

Error due to optical refraction effect

Air's density changes with altitude, causing optical refraction and the aiming beam to bend. This error varies depending on the time of day and climatic conditions.

Measure: 

- Avoid measuring at noon when the temperature is high, instead measure in the early morning or late afternoon to reduce errors.  

- Place the machine at a height of at least 1.5m to avoid the influence of airflow close to the ground.  

- Conduct two-way measurements at different times of the day to get the most accurate data.  

Testing conditions for medium precision leveling machines

1. Check and adjust the operation of parts  

   Make sure the screws, optical knobs, eyeglass adjustment rims and other parts of the leveler work normally and are not stuck or loose.  

2. Check lens quality and determine specifications  

   Includes magnification, viewing area, distance multiplier (K), addition constant (C) and factors affecting measurement accuracy.  

3. Determine the value of the division on the long tube  

   Evaluate the accuracy of the division on the long tube to ensure the measurement results are not misleading.  

4. Check and adjust the standard position of the cross membrane  

   Make sure the vertical thread and rotation axis of the machine are on the same plane, and the horizontal thread must be perpendicular to that plane to avoid errors when measuring.  

5. Check and adjust the balance between the long water tube and the round water tube 

Adjust the water tube to bring the machine's rotation axis to a vertical position, avoiding affecting the accuracy of the measurement.  

6. Test and adjust the basic conditions of the machine  

   - Make sure the axis of the long tube (LL) is parallel to the viewing axis (cc) to ensure measurement accuracy.  

   - Check the diagonal error, ensure that the projections of the LL and cc axes on the horizontal plane are not skewed.  

   - Check the angle error i, make sure the viewing axis and the long tube axis are parallel on the vertical plane.

7. Test the stability of the viewing axis when adjusting the optical sight  

Make sure the view axis does not change position when adjusting focus to avoid errors.  

8. Testing the self-adjusting error of the self-balancing unit (Kompesator)  

For leveling machines with self-balancing function, it is necessary to check the self-adjustment ability to ensure that the viewing axis and the axis of the long level tube are always parallel, minimizing angular error i.  

Conclude:

Above is a summary of errors when using a leveling machine and the concept of a leveling machine. Hopefully the information compiled from EMIN will help readers make more appropriate choices AND consider before making a purchasing decision.