Seeking advice on instrument accuracy calibration
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The accuracy of a certain instrument product is 0.065%. A reference gauge with an accuracy of 0.2 is being used to calibrate our company’s products, on the grounds that an accuracy of 0.5 would be sufficient for our needs. Is this reasoning valid?
The accuracy of instruments is specified from two aspects: requirements for trade settlement and production process control. Process control instruments generally only need to meet the requirements for process control and product quality. The relevant regulations describe the requirements for its degraded use. The situation you are referring to is exactly that kind.
According to the regulations regarding measuring instruments, calibration must be carried out using equipment that is 4 times less precise than the standard equipment; at a precision of 0.065%, it is necessary to use equipment with a precision of at least 0.065%/4 = 0.01625% for testing and calibration. Therefore, such measurement practices are nonsense, and those manufacturers that produce products with a precision of 0.065% (especially some imported brands) are even more absurd.
Moreover, using a device with a precision of 0.2 for testing can only prove that it meets the accuracy requirement of 0.2*4=0.8; therefore, it is incorrect to claim that it meets an accuracy standard of 0.5.
The absolute maximum allowable error of the standard instrument shall not be greater than 1/4 of the absolute maximum allowable error of the instrument under test
The requirements for checksum calibration are still different, right?~
1. In national standards, there is no accuracy level of 0.065; it can only be treated as a 0.1 level calibration. 2. To calibrate instruments at the 0.1 level, standard devices of 0.02 level or higher are required. 3. When an instrument is used at a lower level, for example as if it were a 0.5 level instrument, then to calibrate such an instrument at the 0.5 level, standard devices of 0.1 level or higher are needed
4. If you don’t request a downgrade calibration of the instrument, I doubt the metrology institute will conduct the calibration at the 0.5 class level Inspecting 0.1-grade instruments incurs high inspection costs! Bro, I don’t believe that the measurement institute would be averse to money or hate making more profits~~~ :lol
You know, buddy – many measurement institutes are already satisfied with pressure gauges of 0.02 grade; many of them use gauges of 0.05 grade. That’s why I say it’s nonsense for many imported instruments to be manufactured with 0.065 grade accuracy – after all, it’s practically impossible in China to verify whether such instruments meet the required standards. Surely we can’t send them to the department responsible for standard materials just because of these instruments
Regarding pressure, both the provincial metrology institutes and the regional metrology institutes establish standards at the 0.005 level. They can detect up to 0.01 level. In pressure gauge manufacturing enterprises, standard instruments of class 0.02 and class 0.01 are also quite common these days. . . A few companies at the 0.005 level also have them.
Bro, it’s at level 0.005; the highest certificate that can be issued is one for level 0.02. Generally, once a pressure gauge of this kind is made, it can be sold on the market