Class A albedometer 3S-ALBEDO

for photovoltaic systemsfor photovoltaic systems

Product overview
The 3S-ALBEDO PV albedometer measures plane-of-array (POA) irradiance and reflected irradiance and computes solar albedo (reflected/incident) for bifacial solar panels. It includes a built-in reference cell temperature sensor, is supplied with a mounting bracket and a 3 m UV- and weather-resistant cable, and outputs measured data via RS485 using Modbus RTU.

How it works

• A monocrystalline reference cell (31 × 31 mm) absorbs sunlight and generates current proportional to irradiance.
• A precision shunt resistor converts cell current into measurable voltage signals.
• An internal PT1000 temperature sensor compensates cell output for temperature effects.
• On-board electronics calculate temperature-compensated irradiance values in W/m² and derive albedo.
• Measured values are transmitted to dataloggers or monitoring units via RS485 (Modbus RTU) at up to 38400 Baud.

Measured parameters

• POA (plane-of-array) irradiance
• Reflected irradiance
• Solar albedo (reflected / incident)
• Internal reference cell temperature (optional external module temperatures on 3S-ALBEDO-2T via 2 × PT1000)

Technical specifications
Sensor type: Silicone reference cell (31 × 31 mm)
Irradiance range: 0 – 1600 W/m²
Albedo range: GH 0–1 (POA > 0)
Uncertainty: ≤1% (Class A per IEC 61724-1) —
Resolution: 0.1 W/m²
Response time: 1 s (configurable to 0.5 s)
Field of view: 170°
Output rate: 1/s
Data output: RS485 up to 38400 Baud, Modbus RTU
Power supply: 12–30 V DC; consumption ~20–22 mA @ 24 V DC
Cable: 3 m, UV- and weather-resistant PUR cable
Housing: Aluminium; IP54 standard (optional IP65/IP68)
Operating temperature: -40°C … +85°C
Dimensions: 138 × 112 × 39 mm (L × W × H)
Weight: ~0.52–0.53 kg
Calibration: Each sensor calibrated on Class AAA sun simulator per IEC 60904-2 / IEC 60904-4; reference cell traceable to ISFH (Germany)

Why choose the 3S-ALBEDO

• IEC 61724-1 Class A performance with uncertainty ≤1% (factory calibrated).
• Fast response: standard 1 s, configurable to 0.5 s for higher temporal resolution.
• Robust installation: aluminium housing and UV-resistant cable with IP54 (optional IP65/IP68) for outdoor PV deployment.
• Plug-and-run: supplied with mounting bracket and pre-wired cable for straightforward installation.
• Expandable monitoring: 3S-ALBEDO-2T supports 2 × external PT1000 module temperature sensors for enhanced module diagnostics.

Available models
3S-ALBEDO — RS485 Modbus RTU; measured: POA irradiance, reflected irradiance, solar albedo, 2× cell temperature.
3S-ALBEDO-2T — same outputs plus support for 2 × PT1000 external module temperature sensors.

Features / technical data

• Model: 3S-ALBEDO (also available 3S-ALBEDO-2T)
• Sensor: Silicone reference cell 31 × 31 mm
• Measured data: POA irradiance, reflected irradiance, albedo, cell/module temperatures
• Irradiance range: 0–1600 W/m²
• Uncertainty: ≤1% (IEC 61724-1 Class A)
• Resolution: 0.1 W/m²
• Response time: 1 s (configurable to 0.5 s)
• Field of view: 170°
• Communication: RS485, Modbus RTU (up to 38400 Baud)
• Power: 12–30 V DC; ~20–22 mA @ 24 V DC
• Cable: 3 m PUR, UV- and weather-resistant
• Galvanic isolation: 1000 V between power and RS485 bus
• Module sensor: Class A PT1000 (EN 60751:2022)
• Operating range: -40°C to +85°C
• Dimensions & weight: 138 × 112 × 39 mm; ~0.52–0.53 kg
• IP rating: IP54 standard (optional IP65, IP68)
• Standards & calibration: IEC 61724-1:2021; IEC 60904 series; Class AAA sun simulator calibration traceable to ISFH
• Recommended recalibration: every 2 years
• Warranty: 2 years