Error Analysis of Automatic Detection and Verification System of Illuminance Meter
working principle
During the verification process of the illuminance meter, the motor of the standard lamp displacement system uses the pulley mechanism installed on the guide rail to make the standard lamp move to the position of L1 according to the instructions of the program, and then sends PLC instructions to the automatic turntable, and the PLC of the turntable uses Send relevant instructions to the automatic acquisition system through RS232, so that the illuminance value of the first illuminance meter can be obtained, and the value is converted into a file format and saved. After completion, the automatic collection and identification system sends instructions to the displacement system of the standard lamp, and the standard lamp is transmitted to the L2 position through the motor, and then sends an instruction to the automatic turntable system again, and then the motor on the turntable turns the second illuminance meter After arriving at the position to be tested, after reaching the position to be tested, the command is output again, so that the specific illuminance value of the second illuminance meter can be obtained, and then stored in the relevant file again, and the cycle is repeated according to this process. After the reading and testing of the eighth or more units are completed, the system will automatically stop operating.
Uncertainty Analysis of Calibration Result of Illuminance Meter Automatic Verification System
There are many factors that affect the uncertainty of the measurement results of the light meter, such as the calculation error of the relevant formula, the unevenness of the light track and the influence of different positions on the light track on the measurement results, the vibration and air generated during the movement of the standard lamp. The influence of disturbance, the influence of temperature and humidity fluctuation or deviation, etc. This paper mainly compares the distance deviation caused by the adjustment of the sensor and the filament plane from five aspects, including the repeatability measurement of the illuminance meter, the accuracy of the standard lamp, the accuracy of the electrical measurement system, the distance measurement accuracy, and the distance deviation caused by the adjustment of the light sensor and the filament plane. In five aspects, the uncertainty of the measurement results of the illuminometer verification is analyzed and discussed.
System error analysis and processing
The reasons for the system error of the automatic verification system are: ① the accuracy of the standard light intensity value; ② the accuracy of the electrical measuring instrument; ③ the theoretical method, the standard light can only be approximately equivalent to a point light source, if the distance is too short, the error will increase ; ④ The error of the ranging meter; ⑤ The adjustment of the light sensor causes the distance from the filament plane to change. The causes of the above-mentioned errors are predictable, and the generation of errors can be reduced by means of early prevention, and secondly, the measurement results can be corrected to reduce the errors. Second, the measurement results can be corrected to reduce the error.
In the actual operation process, it is necessary to operate the instrument according to the specification requirements, do a good job of calibration, do a good job of warming up the instrument before testing, find problems in time, solve them, and avoid unnecessary errors. For example, in order to avoid changes in the zero position during the measurement process, each stage of the measurement needs to pay attention to checking the zero position. In order to avoid the accuracy of the instrument due to long-term use or environmental influences, the traceability of the instrument’s standard substance should be done. Periodic inspections and regular inspections and maintenance are carried out on time.
