introduction
In the daily work dealing with instruments and instruments, I often come into contact with the three terms of verification, calibration and verification. What are the differences and connections between the three? First we analyze the concept of the three, as follows:
First, the verification
The legal metrology department or the statutory authorized organization shall, in accordance with the verification procedures, provide evidence through experiments to determine the activities in which the indication errors of the measuring instruments meet the specified requirements.
Second, calibration
Under the specified conditions, in order to determine the indication value of the measuring instrument or the measuring system, or the indication value represented by the physical measuring instrument or the standard substance, the same measured object is tested by the high-precision qualified standard equipment and the metered equipment. A set of operations of the metered device relative to the standard device error is obtained, thereby obtaining a correction value of the indicator data of the metered device.
Third, check
Self-study procedures developed by the company in the absence of verification or calibration procedures. Mainly used for special measuring instruments, or relatively low-precision measuring instruments and testing hardware or software.
Since the term "verification" has rarely been used in recent years, the key verification and calibration are introduced.
Since the term "verification" has rarely been used in recent years, the key verification and calibration are introduced. 
The difference between verification and calibration
1, the purpose is different
The purpose of the verification is to perform a mandatory comprehensive assessment of the measuring device. This comprehensive assessment belongs to the scope of uniformity of values, and is a top-down process of magnitude transfer. The verification shall assess whether the measuring instrument meets the specified requirements.
This requirement is the error range specified by the measuring device verification procedure. Through the verification, it is assessed whether the error range of the measuring device is within the specified error range.
The purpose of the calibration is to evaluate the indication error of the measuring device against the measurement standard, to ensure that the quantity is accurate, and belongs to a set of operations traced from the bottom-up value.
This indication error shall be assessed in accordance with the organization's calibration procedures, in accordance with the calibration cycle, and the calibration record and calibration mark shall be made.
2, different objects
The object of the verification is the measurement device for the mandatory verification specified in China's measurement method. The objects of the verification are mainly three types of measuring instruments: 1. Measurement standards (including international measurement standards and national measurement standards). 2. Measurement standards. 3. The measurement method stipulates 59 kinds of measuring instruments listed in the strong inspection catalogue. The object of calibration is a measuring device that is outside the mandatory test. China's non-mandatory verification measuring devices mainly refer to measuring instruments used in a large number in the production and service provision process, including the measuring instruments used in incoming inspection, process inspection and final product inspection.
3, different nature
Verification is a mandatory law enforcement act and falls within the scope of legal metrology management. Calibration is not mandatory and is a voluntary traceability of the organization.
4, according to different
The main basis for the verification is the National Metrology Verification Regulations (JJG), which is a statutory technical document that must be observed for the verification of measuring equipment. These procedures are statistical documents that are not mandated by the organization and must be developed by an approved authorized metrology department. The main basis for calibration is the “Calibration Specification†formulated by the organization according to actual needs, or in accordance with the requirements of the National Metrology Technical Specification (JJF).
5, different ways
The verification must be carried out in a qualified metrology department or a legally authorized unit. According to China's current situation, most production and service organizations do not have qualifications for verification. Only a few large organizations or professional metrological verification departments have such qualifications. The method of calibration can be carried out by means of self-study, external school, or self-study plus external school. The organization can calibrate the measuring instruments by self-calibration when conditions are met, thus saving a lot of money.
6, different cycles
The period of verification must be carried out in accordance with the provisions of the "Regulations", the organization can not determine. The verification cycle is a mandatory constraint. The calibration cycle is determined by the organization based on the needs of the metering device. It can be calibrated periodically or irregularly or calibrated before use.
7, the content is different
The content of the verification is a comprehensive assessment of the measuring device, the requirements are more comprehensive, in addition to the entire content of the calibration, the relevant items need to be verified. The content and items of the calibration are only to assess the indication error of the measuring device to ensure accurate values.
8, the conclusion is different
The verification must be based on the range of magnitude error specified in the “Verification Regulations†to give a judgment on the pass and fail of the measuring device. Exceeding the range of error specified in the "Verification Regulations" is unqualified, and is within the specified range of error. The result of the verification is the "certification certificate".
The conclusion of the calibration is only to assess the magnitude error of the measuring device, to ensure that the magnitude is accurate, and that no pass or fail determination is required. The results of the calibration can be given a Calibration Certificate or a Calibration Report.
9. Different legal effects
The conclusion of the verification has legal effect and can be used as the legal basis for the verification of measuring instruments or measuring devices. The "certification certificate" is a technical document with legal effect. The conclusion of the calibration does not have legal effect. The calibration certificate given only indicates the magnitude error and belongs to a technical document. It can be seen from the above that the verification, calibration and calibration are not completely independent. The calibration process is included in the verification and verification, but it is only a question of whether the calibration result is given.
Calibration, calibration, calibration options
1. The inspections belonging to the national compulsory verification catalogue are mainly used for occasions with legal requirements. For example, the pressure gauge on the boiler of the enterprise should be sent for inspection regularly.
2. Outside the national mandatory certification list, but there are JJG standards or JJF standards, for inspection or calibration, the company has standard equipment, appliances and calibration methods, which can be self-calibrated. Mainly used for high accuracy requirements, or subject to conditions, must use lower accuracy measuring instruments for higher measurement requirements, which is the most common method used by enterprises, such as calibration of most instruments on production equipment.
3. There is no JJG standard, JJF standard, self-checking. It is mainly used in applications where there is no verification procedure or it is impossible to fully meet the requirements of the regulations but can meet the requirements of use. This is also a common method used by companies.
USB Cable :1.Type A: almost every USB cable has a standard flat rectangular interface at one end. Most computers have a usb-a port to connect to only one USB port.
2.Type-B: almost square connector for printers and other active devices connected to computers. They are not common now because most devices have been moved to smaller connections.
3.Mini USB: a smaller connector type that was standard for mobile devices before micro USB. It's not common today, but you'll see it on some cameras, PlayStation 3 controllers, MP3 players, etc.
4.Micro USB: the current standard for mobile and portable devices, even smaller than Mini USB. Although you can still find micro USB on smartphones, tablets, USB battery packs and game controllers, some have turned to usb-c
5.Type-C: the latest USB standard, which is a reversible cable, promises higher transmission speed and higher power than previous USB types. It can also take into account a variety of functions.
USB Cable
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