Calibration methods and procedures for the use of illuminance meters
Illuminance meter is a specialized instrument for measuring luminosity and brightness. It is to measure the intensity of light (illuminance) is the degree of illumination of the object, that is, the surface of the object received by the luminous flux and the ratio of the illuminated area. Illuminance meter is usually composed of selenium photocell or silicon photocell and microampere meter.
Calibration method of illuminance meter:
The use of light intensity standard lamp, in close proximity to the working distance of the point light source, change the photocell and the standard lamp distance l, recorded under the distance under the ammeter readings, by the distance inverse square law E = I / r2 calculation of light illuminance E, from which a series of different illuminance of the light current value i, for the photocurrent i and the illuminance E curve, that is, for the illuminance meter calibration curve can be made from this dial of the illuminance meter. Indexing that is the calibration of the illuminance meter
Factors affecting the calibration curve:
Photocells and ammeter replacement needs to be re-calibrated; illuminance meter after a period of time should be re-calibrated illuminance meter (generally 1-2 times a year should be verified); high-precision illuminance meter can be used to check the light intensity of the standard lamp; expanding the range of illuminance meter can be changed to calibrate the distance r, you can also choose a different standard lamps, the choice of a small range of the ammeter.
Steps for the use of illuminance meter:
① Turn on the power.
② Open the cover of the light detector and place the light detector horizontally in the measurement position.
③Select the appropriate measurement gear. If the left end of the display only shows "1", it means that the illumination is too much, you need to press the range key (⑧ key), adjust the measurement times.
④ The illuminance meter starts to work and shows the illuminance value on the display.
⑤ The data shown on the display changes constantly, when the display data is more stable, press the HOLD key (⑧ key) to lock the data.
⑥ Read and record the observed value displayed in the readout. The observed value is equal to the product of the displayed number and the range value in the reader. For example: the screen displays 500, the lower right corner of the display state is "× 2000", the illuminance measurement value of 1,000,000lx, that is (500 × 2000).
⑦ Press the lock switch again to cancel the reading value lock function.
⑧ Each observation, three consecutive readings and record.
⑨ After each measurement is completed, press the power switch button to cut off the power supply.
⑩Cover the lid of the light detector and put it back in the box.
