TECHNICAL SPECIFICATIONS OF IRRADIANCE SENSOR

Item Code	3S-IS, 3S-IS-1, 3S-IS-2, 3S-IS-2T, 3S-IS-3, 3S-IS-4, 3S-IS-5
Reference Cell	Monocrystalline Silicon (31 mm x 31 mm)
Current Shunt	High precision shunt resistor directly soldered to the terminals of the cell
Irradiance Range	0 – 1600 W/m²
Uncertainty	≤1%, as per IEC61724-1 standard Class A
Resolution	0.1 W/m², as per IEC61724-1 standard Class A
Response Time	1 sec. as per IEC61724-1 standard Class A
Drift	Very small drift of <0.3%/ year
Field of View	Larger than 160° as per IEC61724-1 standard Class A
Tilt-Azimuthal Angle	0°- 0° , ≤ 1°; as per IEC61724-1 standard Class A
Output Rate	1/s
Data Output	RS485 up to 38400 Baud
Communication Protocol	Modbus RTU
Power Supply	12 to 30 V DC
Power Consumption	30 mA max @24 VDC
Electrical Connection	3 m LIYYC11Y 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	-40°C to +85°C
Operating Humidity Range	0 to 100 %
Box Dimensions	140 mm x 110 mm x 42 mm (W x L x H)
Weight	0.3 kg
IP Rating	IP54 (IP65, IP68 options)
Sensor Housing Material	Aluminum
Compliant Standard	IEC 61724-1:2021 and IEC 60904
Calibration	Each sensor is calibrated under Class AAA Sun Simulator as per IEC 60904-2 and IEC 60904-4 by using a reference cell calibrated by ISFH-Germany
Test	The test is carried under natural sunlight by using a calibrated reference cell from Fraunhofer ISE, Germany

What Does an Irradiance Sensor Do?

Solar irradiance is the amount of solar power received per unit area (W/m²). Monitoring irradiance is essential for evaluating the performance of PV plants. The 3S-IS sensor measures irradiance using a monocrystalline silicon solar cell, while also compensating for temperature effects thanks to its built-in PT1000 cell temperature sensor.

How Does the 3S-IS Sensor Work?

• A monocrystalline solar cell absorbs sunlight and generates current.
• A precision shunt resistor converts this current into measurable signals.
• The temperature sensor at the back of the cell corrects deviations caused by heat.
• An electronic card processes these signals and calculates compensated irradiance values in W/m².
• Data is sent to receiver units via RS485 using Modbus RTU.

Because of its flexible design, the 3S-IS can also link with additional environmental sensors, turning it into a complete monitoring hub for PV plants.

Why Choose the 3S-IS Irradiance Sensor?

• Trusted accuracy: IEC 61724-1 Class A compliance with uncertainty ≤1%, calibrated as per IEC 60904-2 standards.
• Fast results: Response time of one second for real-time decision making. It can be reduced to 500 milliseconds upon request.
• Built to last: A UV-protected IP54 aluminum housing with optional IP65/IP68 ensures reliable operation in demanding outdoor environments.
• Quick setup: Plug-and-run design means fewer installation errors and faster commissioning. Supplied with mounting bracket and cable. Easy integration with any Modbus-compatible PLC, SCADA, or datalogger.
• Expandable: Supports connection of multiple external sensors (temperature, wind, humidity) for more complete monitoring.

Available Models of the 3S-IS Irradiance Sensor

All models below are IEC 61724-1:2021 Class A compliant, factory-calibrated, and built with the same durable construction. The only difference is the number and type of external sensors that can be connected via RS485 Modbus RTU.

Model	Communication	Uncertainty	External Sensor Options
3S-IS	RS485 Modbus RTU	≤1%, as per IEC61724-1 standard Class A	No external sensor can be connected
3S-IS-1	RS485 Modbus RTU	≤1%, as per IEC61724-1 standard Class A	Ambient Temperature Sensor OR Module Temperature Sensor
3S-IS-2	RS485 Modbus RTU	≤1%, as per IEC61724-1 standard Class A	Ambient Temperature Sensor OR Module Temperature Sensor Wind Speed Sensor
3S-IS-2T	RS485 Modbus RTU	≤1%, as per IEC61724-1 standard Class A	Ambient Temperature Sensor Module Temperature Sensor
3S-IS-3	RS485 Modbus RTU	≤1%, as per IEC61724-1 standard Class A	Ambient Temperature Sensor Module Temperature Sensor Wind Speed Sensor
3S-IS-4	RS485 Modbus RTU	≤1%, as per IEC61724-1 standard Class A	Ambient Temperature Sensor Module Temperature Sensor Wind Speed Sensor Wind Direction Sensor OR Relative Humidity Sensor
3S-IS-5	RS485 Modbus RTU	≤1%, as per IEC61724-1 standard Class A	Module Temperature Sensor Wind Speed Sensor Wind Direction Sensor Relative Humidity and Ambient Temperature Sensor

Frequently Asked Questions (FAQ)

1- Which datalogger brands are SEVEN irradiance sensors compatible with?

SEVEN irradiance sensors are compatible with a wide range of well-known datalogger brands, including:

• ABB
• Bluelog
• DEIF
• Elum
• Encombi
• Fimer
• General Electric
• GoodWe
• Growatt
• Hopewind
• Huawei
• Kehua Tech
• Sico
• SMA
• Solplanet
• SolarEdge
• Solar-Log
• SolaX Power
• Solis
• Sungrow
• SUNVEC
• Wattch MET
• Webdyn

2- What is the uncertainty of the irradiance sensor?

The uncertainty is ≤1%, fully compliant with IEC 61724-1 Class A requirements.

3- Can this sensor connect directly to my SCADA system?

Yes, as long as your system supports RS485/Modbus RTU, the sensor will be fully compatible.

4- How are the sensors tested and calibrated?

Each irradiance sensor is calibrated under a Class AAA Sun Simulator as per IEC 60904-2 and IEC 60904-4, using a reference cell calibrated by ISFH-Germany.

The sensors are tested in natural sunlight against a reference cell calibrated by the Fraunhofer ISE Institute.

5- How often should I recalibrate the sensor?

Recalibration every 2 years is recommended by IEC standards for maximum accuracy.

6- Where can I recalibrate the irradiance sensor?

SEVEN Sensor provides calibration services at its facilities. Calibration is performed using a Class AAA Sun Simulator, in accordance with IEC 60904-2 and IEC 60904-4 standards, and referenced against a calibration cell certified by the ISFH Institute in Germany.

Additionally we offer user-friendly interface where users can recalibrate the sensors in their home country and enter the new calibration values into the system.

7- Are the irradiance sensors Class A?

Yes. All SEVEN irradiance sensor models — 3S-IS, 3S-IS-1, 3S-IS-2, 3S-IS-2T, 3S-IS-3, 3S-IS-4, and 3S-IS-5 — are Class A as per IEC standards, with the exception of the low-cost irradiance sensor.

8- What is the price of irradiance sensors?

Depending on the model and included accessories, the 3S-IS series is available between 300 and 600 EUR.

9- Does the sensor include a cable?

Each unit comes with a 3 m LIYYC11Y PUR cable (UV and weather resistant) with 6 wires twisted (including ground for both Data & Power). Other lengths are available on request.

10- What makes this sensor different from analog models?

Unlike analog outputs, Modbus RTU provides digital communication, minimizing signal loss over long distances and allowing multi-sensor connections.

11- What are the delivery times?

• Small orders: approx. 3-5 days
• Bulk orders (100 pcs): approx. 4-6 weeks

12- How do I set up the sensor?

Follow our user manual, setting instructions and YouTube video guides, which include step-by-step instructions for configuring the sensors with well-known datalogger brands such as SMA, Huawei, and Sungrow. We also provide remote setup support if needed.

13- What is the warranty?

All 3S-IS sensors come with a 5-year warranty.

14- What external sensors can be connected to the irradiance sensor?

The SEVEN irradiance sensor can also function as a hub, supporting the connection of external sensors such as:

• Module temperature sensors
• Ambient temperature sensors
• Wind speed sensors
• Wind direction sensors
• Relative humidity sensors