Seven Sensor Self Cleaning Irradiance Sensor 3S-SCIS
Seven Sensor 3S-SCIS is a Class A irradiance sensor with an automatic cleaning system designed for photovoltaic installations. It measures the solar irradiance on POA in W/m² and is used to calculate the plant’s performance ratio (PR). Thanks to its self-cleaning system, it regularly cleans itself, thus reducing measurement deviations caused by dirt accumulation and minimizing the need for manual cleaning. All measured data is transmitted to data loggers via Modbus RTU over RS485.
A cleaning system consisting of a water tank, pump, and hose line is connected to the sensor. The system washes the sensor surface at a time determined via a user interface (GUI).
- Scheduling: By default, cleaning runs once a day at a time specified by the user. If desired, the number of daily cleanings can be increased to three by defining three different times via the GUI.
- Water consumption: An 18-liter tank is typically refilled twice a year, with an annual water consumption of approximately 36 litres for daily cleaned sensors.
- Water hose: The standard hose length is 5 meters and can be extended up to 20 meters upon request. The maximum height of the water line is 5 meters.
The 3S-SCIS incorporates a real photovoltaic reference cell. This cell reacts to light just like a solar panel, so the sensor mirrors the conditions that the panels actually see. A Class A PT1000 temperature sensor behind the cell corrects for the effect of temperature on the measurement.
The device calculates the temperature-compensated irradiance value in W/m² and transmits it to data loggers via Modbus RTU over an RS485 line. Each sensor is calibrated under a Class AAA Sun Simulator according to IEC 60904-2 and IEC 60904-4 standards using a reference cell calibrated by the ISFH Institute in Germany.
What Are the Advantages of Self Cleaning Irradiance Sensor?
The self-cleaning irradiance sensor offers several advantages for reliable and low-maintenance solar monitoring as outlined below.
- Automatic cleaning: It cleans the sensor automatically at regular intervals, reducing labour costs by eliminating the need for manual cleaning and field visits.
- Class A compliant: Meets IEC 61724-1:2021 Class A monitoring requirements with an uncertainty of <1%.
- Similar behaviour to with panels: The PV reference cell has a similar structure to the panels and responds to light in the same way.
- Easy integration: Connects to data loggers via Modbus RTU output over RS485 and SunSpec compatibility.
- Flexible power supply: Operates with 110-240 V AC or 24 V DC.
- Backed by SEVEN: Comes with remote installation service, free software updates and a 2-year warranty.
Product Details
Deskripsi
Technical Specifications of Self Cleaning Irradiance Sensor
| Item Code | 3S-SCIS |
| Measured Data | Irradiance and Cell Temp. |
| Irradiance Range | 0…1600 W/m² |
| Uncertainty | ≤1% (Less than 2%; as per IEC 61724-1 standard Class A) |
| Resolution | 0,1 W/m² (Less than 1 W/m²; as per IEC 61724-1 standard Class A) |
| Response Time | 1 sec. (Less than 3 sec; as per IEC 61724-1 standard Class A) |
| Drift | <0,3% / year |
| Field of View | 170° (Larger than 160° as per IEC 61724-1 standard Class A) |
| Tilt-Azimuthal Angle | 0°- 0° (≤1°; as per IEC 61724-1 standard Class A) |
| Output Rate | 1/s |
| Data Output | RS485 up to 38400 Baud |
| Communication Protocol | Modbus RTU |
| Power Supply | 110-240V AC or 24V 5A DC |
| Power Consumption | Pump Passive: Max. 20 mA @ 24V DC; Pump Active: Max. 3 A @ 24V DC |
| Cabel Length and Features | 3 m LI2Y(st)C11Y PUR Cable, UV and Weather Resistant |
| Galvanic Isolation | 1000 V between power supply and RS485 bus |
| Cell Temperature Sensor Type | PT1000 Class A as per EN 60751 |
| Operating Temperature Range | -20°C…85°C |
| Operating Humidity Range | 0%…100% RH |
| Water Tank Capacity | 18 Liters |
| Water Consumption | 36 Liters/year (Refilling required twice a year for daily cleaning) |
| Washing Liquid | Pure Water: 100% (Should be used when the ambient temperature is above 0°C); Pure Water: 65% + Antifreeze: 35% (Should be used when the ambient temperature is below 0°C) |
| Water Hose Length | 5 m (up to 20m on request) |
| Max. Water Line Height | 5 m |
| Weight | 10 kg |
| IP Rating | IP54 (Optional IP 65, IP 68) |
| Sensor Housing Material | Aluminium |
| Standard | IEC 61724-1:2021 and IEC 60904 |
| Calibration | Each sensor is calibrated under a Class AAA Sun Simulator according to IEC 60904-2 and IEC 60904-4 standards using a reference cell calibrated by the ISFH Institute in Germany. |
| Origin | Türkiye |
Why is Sensor Cleaning Important for Accurate Readings?
The surface of the irradiance sensor becomes dusty and dirty over time. A dirty sensor will read lower irradiance levels, which can falsify calculations such as the performance ratio. Therefore, keeping the sensor clean is essential in Class A monitoring.
The IEC 61724-1:2021 standard (clause 8.2.5 and Table 7) mandates the reduction of contamination effects on irradiance sensors within the scope of Class A monitoring and requires at least weekly cleaning in typical installations. Technologies that provide contamination reduction equivalent to weekly cleaning are also accepted. 3S-SCIS is designed precisely to meet this requirement.
Automatic cleaning eliminates the need for regular field visits to manually clean the sensor. This reduces labour costs and ensures the sensor remains clean and provides consistently accurate measurements.
