1 SUN is determined by:<\/h3>\n\n\n\n
This series evaluates irradiance stability during continuous illumination.<\/p>\n\n\n\n
- \n
- The sensitivity constant stated in the calibration certificate (\u00b5V\/W\/m\u00b2) corresponding to AM1.5G<\/li>\n\n\n\n
- The pyranometer output voltage<\/li>\n<\/ul>\n\n\n\n
Accordingly:<\/h3>\n\n\n\n
1 SUN is defined as the output voltage corresponding to 1000 W\/m\u00b2 based on the calibrated sensitivity constant.<\/p>\n\n\n\n
This measurement is conducted under AM1.5G conditions only.<\/p>\n\n\n\n
3. Measurement Items<\/h2>\n\n\n\n
3.1 Irradiance<\/h3>\n\n\n\n
- \n
- Pyranometer (Main)<\/li>\n\n\n\n
- Pyranometer (Main)<\/li>\n<\/ul>\n\n\n\n
3.2 Temperature<\/h3>\n\n\n\n
- \n
- Side temperature of pyranometer (Main)<\/li>\n\n\n\n
- Side temperature of pyranometer (Sub)<\/li>\n\n\n\n
- Temperature of fixture at non-illuminated portion of irradiation plane<\/li>\n\n\n\n
- Ambient temperature near irradiation plane<\/li>\n<\/ul>\n\n\n\n
4. Equipment Used<\/h2>\n\n\n\n
Equipment Name<\/strong><\/td> Manufacturer<\/strong><\/td> Model<\/strong><\/td> S\/N<\/strong><\/td> Remarks<\/strong><\/td><\/tr> Pyranometer (Main)<\/strong><\/td> EKO<\/strong><\/td> ML-020VM<\/strong><\/td> 04<\/strong><\/td> Sensitivity Constant\uff1a<\/strong>
6.96\u03bcV\/W\/\uff4d\u00b2<\/strong><\/td><\/tr>Pyranometer (Sub)<\/strong><\/td> EKO<\/strong><\/td> ML-020VM<\/strong><\/td> 0<\/strong>3<\/td> Sensitivity Constant\uff1a<\/strong>
7.05\u03bcV\/W\/\uff4d\u00b2<\/strong><\/td><\/tr>Multi-input data logger<\/strong><\/td> KEYENCE<\/strong><\/td> NR-500<\/strong><\/td> D3900120<\/strong>
7Y520074<\/strong><\/td>(Main)<\/strong>
(Sub)<\/strong><\/td><\/tr>Temperature and measurement unit<\/strong><\/td> KEYENCE<\/strong><\/td> NR-TH08<\/strong><\/td> 12110317<\/strong>
18010182<\/strong><\/td>(Main)<\/strong>
(Sub)<\/strong><\/td><\/tr>K-type thermocouples<\/strong><\/td> <\/td> <\/td> <\/td> <\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n 5. Measurement Positions<\/h2>\n\n\n\n
- \n
- Main pyranometer positioned at the center of the irradiation plane<\/strong><\/li>\n\n\n\n
- Sub pyranometer placed adjacent to the main sensor<\/strong><\/li>\n\n\n\n
- Effective irradiation area: 50 \u00d7 50 mm<\/strong><\/li>\n\n\n\n
- For smaller irradiation areas, only the main pyranometer is used<\/strong><\/li>\n<\/ul>\n\n\n\n
Thermocouples are positioned:<\/h3>\n\n\n\n
- \n
- On the irradiation plane fixture (non-illuminated area)<\/strong><\/li>\n\n\n\n
- In nearby ambient space without physical contact<\/strong><\/li>\n<\/ul>\n\n\n\n
![\"\"](\"https:\/\/www.san-eielectric.co.jp\/am\/wp-content\/uploads\/2026\/03\/image01.jpg\")
<\/figure>\n\n\n\n6. Measurement Procedure<\/h2>\n\n\n\n
- \n
- Turn on the lamp.<\/li>\n\n\n\n
- Perform a 30-minute warm-up.<\/li>\n\n\n\n
- Open shutter and adjust lamp current to reach 1 SUN.<\/li>\n\n\n\n
- Close shutter and wait 5 minutes.<\/li>\n\n\n\n
- Open shutter and confirm 1 SUN. Readjust if necessary.<\/li>\n\n\n\n
- Close shutter and wait 5 minutes.<\/li>\n\n\n\n
- Start logging (10-second interval).<\/li>\n\n\n\n
- Open shutter and perform 24-hour continuous measurement.<\/li>\n\n\n\n
- Close shutter after 24 hours and stop logging.<\/li>\n\n\n\n
- Analyze and evaluate data.<\/li>\n<\/ol>\n\n\n\n
7. Data Handling<\/h2>\n\n\n\n
- \n
- Pyranometer output voltage is treated as primary raw data.<\/li>\n\n\n\n
- Voltage is converted to irradiance (W\/m\u00b2) using the calibrated sensitivity constant.<\/li>\n\n\n\n
- Evaluation is conducted using both voltage and converted irradiance values.<\/li>\n<\/ul>\n\n\n\n
This ensures transparency and traceability.<\/p>\n\n\n\n
8. Data Analysis Items<\/h2>\n\n\n\n
8.1 Long-Term Variation<\/h3>\n\n\n\n
- \n
- Maximum<\/li>\n\n\n\n
- Minimum<\/li>\n\n\n\n
- Average<\/li>\n\n\n\n
- Variation range (Max \u2212 Min)<\/li>\n\n\n\n
- Temporal variation rate (Range \/ Average)<\/li>\n<\/ul>\n\n\n\n
8.2 Sensor Consistency<\/h3>\n\n\n\n
- \n
- Trend comparison (Main vs Sub)<\/li>\n\n\n\n
- Correlation tendency<\/li>\n<\/ul>\n\n\n\n
8.3 Temperature Influence<\/h3>\n\n\n\n
- \n
- Correlation between irradiance and sensor temperature<\/li>\n\n\n\n
- Correlation between irradiance and ambient temperature<\/li>\n\n\n\n
- Presence of temperature-associated voltage change<\/li>\n<\/ul>\n\n\n\n
9. Stability Evaluation Criteria<\/h2>\n\n\n\n
Stability is evaluated based on:<\/h3>\n\n\n\n
- \n
- Long-term variation remaining within or close to measurement uncertainty.<\/li>\n\n\n\n
- Consistent trends between main and sub sensors.<\/li>\n\n\n\n
- Temperature is not identified as the primary cause of irradiance variation.<\/li>\n<\/ol>\n\n\n\n
Evaluation is made through comprehensive consideration of these factors.<\/p>\n\n\n\n
10. Measurement Uncertainty<\/h2>\n\n\n\n
Uncertainty includes contributions from:<\/h3>\n\n\n\n
- \n
- Calibration uncertainty<\/li>\n\n\n\n
- Sensitivity constant uncertainty<\/li>\n\n\n\n
- Data logger accuracy<\/li>\n\n\n\n
- Temperature dependence<\/li>\n\n\n\n
- Installation and geometric conditions<\/li>\n<\/ul>\n\n\n\n
Overall irradiance measurement uncertainty is approximately \u00b11% as a practical reference.<\/p>\n\n\n\n
Long-term variation evaluation is conducted in consideration of this uncertainty.<\/p>\n\n\n\n
11. Validity of the Measurement Method<\/h2>\n\n\n\n
This measurement examines:<\/h3>\n\n\n\n
- \n
- Reproducibility<\/li>\n\n\n\n
- Temperature influence<\/li>\n\n\n\n
- Shutter influence on lamp behavior<\/li>\n\n\n\n
- Independent cross-check using two pyranometers<\/li>\n<\/ul>\n\n\n\n
The evaluation therefore includes assessment of the measurement methodology itself.<\/p>\n\n\n\n
- In nearby ambient space without physical contact<\/strong><\/li>\n<\/ul>\n\n\n\n
- Sub pyranometer placed adjacent to the main sensor<\/strong><\/li>\n\n\n\n
- Main pyranometer positioned at the center of the irradiation plane<\/strong><\/li>\n\n\n\n