With the development of science and technology, there are more and more types of colorimeter instruments, and the measurement performance of different colorimeters has significant differences. No matter which type of colorimeter is used, the accuracy of the measurement results is crucial. Important, so as not to affect the accuracy of the test data. During the verification and use of the colorimeter, it is necessary to ensure the accuracy of the verification data to prevent errors.
The wavelength maximum allowable error and repeatability verification
The maximum allowable error of the wavelength of the colorimeter is the variation range of the wavelength during the verification process. The general colorimeter needs to be controlled between (±0.2-±1) nm. For different types of verification instruments, there will be different verification effects. Yuan lamp has no obvious spectral line change before the wavelength of 365nm. After this value is exceeded, the spectral line can be accurately resolved, but the intensity is low. , In the process of checking the wavelength, the most accurate wavelength values are at 486.0nm and 656.1nm. Therefore, when using the gas lamp to verify the colorimeter, these two wavelengths are generally selected to ensure the best verification effect. In addition to the colorimeterthat can be verified by the Er lamp, the mercury lamp can also complete this work. The mercury lamp itself has a better optical foundation, and the spectral lines are more discrete and clearer. In the process of calibration and calibration, the effect is good, but it is cumbersome to operate. Due to the limitation of the mercury lamp Guangyuan, the mercury lamp needs to be ignited, fixed in a special position, and irradiated on the grating as centrally as possible. The commonly used mercury lamp spectral lines The wavelength is at 546.1nm. In contrast, the ammonium zirconium filter or the Chin filter has more aspects in operation, and is used more frequently and widely in the verification process of the colorimeter.
The maximum allowable error of transmittance and repeatability verification
The maximum allowable error of transmittance can reflect the accuracy of the light measurement of the monitoring instrument. The repeatability verification requires the verification personnel to repeatedly measure the repeatability of any peak absorbance in the process of verifying the colorimeter. During the verification process of the colorimeter, the accuracy will change with the change of the measuring range of the verification instrument. Generally, it is: 0.0015A-±0.0005A, and the photometric repeatability is generally: 0.001A±0.001A±0.002A. In the verification process of colorimeter, the maximum allowable error verification of transmittance can be divided into two ways. The verification process can be completed by using a standard solution or standard filter. In the actual verification process of the colorimeter, the value of the transmittance often exceeds the range. The reason is not always the accuracy of the colorimeter itself. Errors or slight deformation of the filter shell will not affect the accuracy of the colorimeter during measurement, so it will not affect the verification results.
Questions about the stray light
The stray light of the handheld color meter directly determines its reliability and working reliability. If there is too much stray light, it will affect the continuity of the spectral line and seriously affect the measurement accuracy of the colorimeter. Stray light can be considered as the light of other wavelengths in the receiver except the specified wavelength range. If the wavelength of the stray light is the same as the measured wavelength, the stray light will hit the detector due to the reflection of the detection sample itself, and if the stray light is the same as the measured wavelength. Astigmatism outside the wavelength range will be affected by dust, scratches, etc., and cannot reach the specified detector light.
Sensitivity file | Stray light error(%) |
2files | 0.5 |
3files | 1.2 |
4files | 1.8 |
5files | 2.1 |
As can be seen from the above table, if the sensitivity level of the colorimeteris too high during the verification process, the corresponding stray light error will also increase, and it is easy to cause zero drift due to the increase of the current, which will cause serious verification. error. Therefore, in the verification process of the colorimeter, the sensitivity gear of the larger gear should not be used to ensure the accuracy of the verification result.