What is the measuring device?

What are the monitoring and measuring devices in the project?

The measurement theory, method and technology in the design, construction and management stages of engineering construction are called "engineering measurement". Engineering survey is the direct application of surveying and mapping science and technology in national economy and national defense construction, and it is the comprehensive application of surveying and mapping science and technology. According to the procedure of engineering construction, engineering investigation can be divided into planning and design stage, construction stage and operation management stage after completion. The survey in the planning and design stage mainly provides topographic data. The method of obtaining terrain data is to carry out ground mapping or aerial photogrammetry on the basis of established control survey. The main task of survey in the construction stage is to accurately calibrate the plane position and elevation of all parts of the building on site according to the design requirements, as the basis for construction and installation. Generally, it is also required to establish a construction control network first, and then carry out various measurement work according to the needs of the project. Measurement in the operation management stage after completion, including completion measurement, deformation observation and maintenance of monitoring project safety. According to the types of projects served by engineering survey, it can also be divided into building engineering survey, line survey, bridge and tunnel survey, mine survey, urban survey and water conservancy project survey. In addition, high-precision positioning and deformation observation for large equipment are also called high-precision engineering survey; The application of photogrammetry technology in engineering construction is called engineering photogrammetry; A measurement system with electronic total station or ground camera as sensor and computer as support is called three-dimensional industrial measurement. Engineering survey directly serves the engineering construction, and its service and application scope include urban construction, geology, railway, transportation, real estate management, water conservancy and electric power, energy, aerospace, national defense and other engineering construction departments. No matter the survey work in each stage of the engineering process or in different projects, it is necessary to select appropriate survey means according to the error analysis and survey adjustment theory, and process and analyze the survey results, that is to say, the survey data processing is also an important content of engineering survey. The development of engineering technology constantly puts forward new requirements for measurement. At the same time, the development of modern science and technology and new surveying and mapping technology has brought severe challenges and excellent opportunities to engineering surveying which directly serves economic construction. Especially with the development of global positioning system (GPS), geographic information system (GIS), photogrammetry and remote sensing (RS), digital mapping and ground survey, the means and methods of engineering survey have undergone profound changes.

What is monitoring and measuring equipment?

Monitoring: refers to the continuous control of the process, such as regularly recording the parameter data of process operation/regularly checking whether the equipment/operators are trained. ...

Measuring equipment and devices: refers to the equipment and devices used to measure products.

If you make measurements, that's what those instruments are usually used for.

What is a measuring tool or measuring instrument? What are these three types?

Measuring tool refers to an instrument used to measure or inspect the size of parts. It has a simple structure and can directly indicate the unit and limit of length. Such as cast iron flat plate, cast iron square, caliper, micrometer, gauge block, knife edge level, etc.

Gauge is an instrument used to measure parts or check measuring tools, and its structure is complex. It is a measuring instrument that magnifies or subdivides the length unit by using the principles of machinery, optics, pneumatics and electricity, such as pneumatic gauge, inductive micrometer, vertical contact interferometer, length gauge and universal tool microscope.

Measuring tools and instruments can generally be divided into:

1, benchmark measuring tools and gauges

Measuring tools-measuring block, polygon prism, linear ruler, etc.

Measuring instruments-laser light wave comparator, light wave interference comparator, vertical optical measuring instrument, etc.

2. General measuring tools and instruments

Measuring tools-cast iron plate, cast iron platform, inspection plate, marking plate, riveting plate, assembly plate, marble plate, platform, caliper, plug gauge, ring gauge, feeler gauge, steel ruler, vernier caliper, depth gauge, etc.

Gauges-dial gauge, dial gauge, lever dial gauge, micrometer, length gauge, optical comparator, etc.

According to its working principle, measuring instruments can also be divided into:

(1) mechanical gauge: a measuring instrument using levers, gears, springs, etc. As a transmission amplification mechanism, and displayed by a reading device.

(2) Optical measuring instrument: a measuring instrument made by amplifying the optical lever according to the principle of light reflection.

(3) Pneumatic measuring instrument: a measuring instrument based on the principle of pressure or airflow change when compressed air flows over the surface of parts.

(4) Electrical measuring instruments: measuring instruments that change the length and size into electric quantity changes such as inductance and capacitance.

3. Measuring tools and instruments

Measuring tools-square, sine gauge, universal square, cone gauge, 7: 24 taper check bar, angle gauge block, etc.

Measuring instruments-level, optical dividing head, optical goniometer and optical composite level, etc.

4. Measuring tools and instruments for detecting geometric shapes and mutual positions.

Measuring tools-cast iron flat plate, cast iron platform, sample ruler, etc.

Measuring tools-deflection tester, roundness tester and flatness tester, etc.

5. Measuring tools and instruments for detecting surface smoothness

Measuring Tool-Smoothness Template.

Measuring instruments-interference microscope, profilometer and light cutting microscope, etc.

6. Measuring tools and instruments for detecting threads

Measuring tools-three pins, thread dial indicator, thread plug gauge, thread ring gauge, etc.

Measuring instruments-pitch measuring instrument, spiral measuring instrument, etc.

7. Measuring tools and instruments for detecting gears

Measuring tools-normal micrometer, gear runout tester, tooth thickness vernier caliper.

Gauges-involute tooth profile tester, pitch tester, basic pitch tester, tooth direction tester, single-sided meshing tester, etc.

8. Special measuring tools and instruments

All kinds of measuring tools and instruments have one thing in common, that is, they must have three basic functions: detecting, comparing and displaying the difference between standard values and measured values, and other functions can meet diversified needs.

What is the systematic error of measuring device? Briefly describe its characteristics, reasons and whether it can be overcome.

Systematic error means that when an unknown quantity is repeatedly measured under the same observation conditions, if the magnitude and sign (positive or negative) of the error value are systematic; Either it changes according to a certain law during the observation process, or it is a constant. This kind of error is called systematic error.

The characteristic of systematic error is that the measurement results deviate in one direction, and its value changes regularly, which is repetitive and cumulative. According to the characteristics of system error, find out the main causes of system error, and take corresponding measures to reduce its influence.

There are three main reasons for the measurement error:

(1) measuring instrument. Defects in the instrument itself or failure to use the instrument according to the specified conditions. Any kind of measuring instrument has a certain accuracy, and the data obtained from this observation must have errors.

(2) observers. The ability of observers to distinguish sensory organs has certain limitations, and the technical level and working attitude of observers directly affect the quality of observation data.

(3) external conditions. External conditions, such as temperature, humidity, air pressure, atmospheric refraction and other factors and their changes will have a direct impact on the observation data.

Methods to eliminate and weaken system errors;

(1) adopts the correction value compensation method. Corrective measures can be taken for the systematic error of the fixed value. Generally, the method of adding correction value is adopted.

(2) eliminate the root causes. Eliminating the error source is a better method to eliminate the system error. This requires surveyors to carefully analyze and study standard devices, measuring environmental conditions and measuring methods. , try to find out the root cause of the system error, and then take measures.

(3) Adopt special observation methods and procedures.

Exchange method: In the measurement, some conditions such as the position of the measured object are exchanged with each other, so that the cause of system error has an opposite influence on the measurement result, thus offsetting the system error.

Replacement method: the replacement method requires two measurements. The first measurement is made on the measured object. After reaching the balance, the measured object is immediately replaced by a known standard value without changing the measurement conditions. If the measuring device can still reach balance, the measured object is equal to the known standard value. If the balance can't be reached, trim it to make it balanced, and then you can get the difference between the measured value and the standard value, that is, the measured value = the standard value difference.

Compensation method: Compensation method requires two measurements, and some conditions in the measurement are changed to make the error values obtained in the two measurement results equal in size and opposite in sign, and the arithmetic average of the two measurements is taken as the measurement result, thus offsetting the system error.

Symmetrical measurement method: that is, before and after measurement, the same known quantity is measured symmetrically, and the average value of the two known quantities is compared with the measured value, so as to obtain the measurement result of eliminating linear system error.

Semi-periodic even number measurement method: for periodic system errors, semi-periodic even number observation method can be adopted, that is, even number of observations are made every half period to eliminate them.

Combined measurement method: it is difficult to analyze the system error that changes according to complex laws. The combined measurement method can make the system error appear in the measured value as much as possible, thus transforming the system error into random error processing.

What are the static characteristics of the test equipment?

The static characteristics of the measuring device refer to describing how close the actual measuring device is to the ideal time-invariant linear system under static measurement, including linearity, sensitivity, return error, resolution, zero drift and sensitivity drift.

What is the principle of leveling?

The principle of leveling method is to measure the height difference between two points by using the horizontal line of sight provided by the level gauge and according to the readings on the leveling ruler erected at two points, so as to calculate the elevation of another point from the known elevation of one point.