Measuring instruments are the third party standards required for measuring in order to obtain some attribute values of the target. Measuring instruments generally have scales, volumes and other units.
Scholars and navigators know very well that if the position of celestial bodies can be accurately measured on the sea, then sailors can know their latitude with certainty. To do this, we need precise measuring instruments.
Ptolemy once described the astrolabe (also called the astrometer). The larger ones are used in observatories and the smaller ones are used on ships. The use of the astrolabe requires the cooperation of three people - one holds the thumb ring on the astrolabe, one aims, and the other reads the results on the dial. When the ship shakes violently, the results are naturally not very accurate. Whenever possible, sailors will go ashore to survey.
Ancient astronomers used a cross ruler to measure the latitude of stars. Later sailors also used it in navigation. The instrument consists of a ruler and a cross ruler, with the lower end of the cross ruler placed in a horizontal position. While observing the celestial body along the ruler, slide the cross ruler until it touches the object (sun or star) in your view, and then read the degree on the ruler. This instrument can be operated by only one person.
Both the astrolabe and the cross ruler require the observer to observe the sun directly. In sunny days, too strong light will make observation impossible. In order to solve this problem, England captain and navigator John Davis invented the back ruler. It is made of a ruler and a sliding crossbar. When observing, the observer first turns his back to the sun, and then slides the crossbar until it casts a shadow in the small disk in front of him. In this way, the observer can observe the horizon.
John Davis also invented the quadrant with the help of Edward Wright, a mathematician from Cambridge. There is an eyepiece on the crossbar of this instrument, through which the observer can observe the horizon and the reflected sun.
Pierre Burger, a hydrogeographer in Kloicik, made further improvements to the object limiter. The improved quadrant enables the observer to see the sun setting on the horizon through the eyepiece.
John Hadley in England invented the octave, which was first tried in 1732. It consists of a reflecting and an alcohol level. This instrument is more accurate than any other instrument used at sea before.
Instrument index
The basic contents of the concept of measuring instrument include: precision, error, measuring standard equipment, length measurement, angle measurement, shape measurement, and traditional optical instruments. Application in precision measurement, etc.
There are two types of measuring instruments: contact test and optical test (most used) contact test: general measuring tools and 3D measuring tools (CMM is also called 3D) CMM is also called 3D, which can measure many complex spatial dimensions, such as molds and automobile products.
Common types
Electronic measuring instrument
Electronic measuring instruments have a unique strategic industry. Its own development has a very obvious impact on the development of the entire national economy, especially the electronic information industry. The market of electronic measuring instruments in China is huge and the demand is large. Electronic measuring instruments play a vital role in the development of electronic information industry.
The development of domestic electronic measurement technology and electronic measurement instruments is rapid, covering all walks of life. First, the basic theoretical research of electronic measurement technology: new testing theory and method research, artificial intelligence theory research, frequency based traceability and standard acquisition method research, new measurement and control bus and system structure research, measurement and instrument standard research and formulation are the key points in the future theoretical research. Second, the development of electronic measurement and measurement technology: the fast developing technologies include advanced measurement and control bus technology, new digital signal processing technology, new comprehensive testing and fault diagnosis technology, optical frequency standard and new precision time-frequency testing technology. The third and second types of important electronic measuring instruments: an important development direction of vector network analyzer is to build automatic measurement technology and automatic testing system with vector network analyzer as the core; In addition, vector network analyzer has stepped out of the application field of traditional linear network and played an important role in the test and analysis of nonlinear and high-power networks. Modulation domain analyzer is the only technology that can directly measure the jitter that changes with time in communication transmission, especially in the field of electronic testing. Fourth, the development of modern production technology of electronic measuring instruments: the design and production level of instrument products is an important symbol to measure a country's scientific and technological industrial foundation and industrial capacity, which runs through the entire production process and life cycle of products. In the future, in the research of instrument production technology, we should pay attention to solving the problems of product design and process supervision mode, researching new instrument devices, developing high-precision and high-quality quality inspection equipment for special instrument components, parts and complete machines, studying virtual test verification and engineering verification technology, studying advanced production processes and processes, and studying new evaluation methods for stability, reliability, maintainability and measurability, And the standardized certification system of products. Fifth, the integrated test system of electronic measuring instruments: the integrated test should focus on the system optimization of the integrated test system, the research on the unity and integrity technology of the measurement and control system, the research on sensor information processing and multi-sensor data fusion technology, and the research on the distributed network interconnection, triggering, synchronization and other technologies of field test in large areas, And the research of reconfigurable measurement and control system technology based on synthetic instruments and systems.