Soiling sensor for photovoltaic applications 3S-SMS-MB-M

for solar PV modulesIEC 61724Modbus RTU

Product Overview
The SEVEN Manual Soiling Sensor measures energy losses on photovoltaic (PV) panels by comparing a clean reference cell and a soiled reference cell. The reported soiling ratio corresponds directly to energy loss (e.g. 10% soiling = 10% energy loss). Measured soiling data are transmitted to data loggers and receiver units over a 3‑wire RS485 bus using Modbus RTU. The device is SunSpec compliant for integration with standard monitoring platforms.

How the Manual Soiling Sensor Works

• One reference surface is kept clean by manual intervention.
• The other reference surface is exposed to the same dust and dirt conditions as the PV modules.
• By comparing irradiance between the clean and dirty cells, the sensor calculates the soiling ratio in real time and transmits it via Modbus RTU over RS485.

Key Benefits

• Financial transparency — quantifies energy and revenue loss due to soiling.
• Data‑driven operations — enables optimized cleaning schedules to reduce costs.
• Suitable for utility‑scale plants, commercial rooftops and industrial projects.
• Weather‑resistant design: IP68 housing, UV‑protected cabling, wide operating temperature range (-40°C to +85°C).
• Proven accuracy: calibrated under Class AAA solar simulator conditions with reference cells certified by ISFH and Fraunhofer ISE.

Maintenance & Operation Notes
The Manual version does not include automatic cleaning; operators must manually keep one reference cell clean (daily cleaning of the clean cell with a wet cloth is recommended). Inspect cables and connectors regularly and verify calibration annually to maintain IEC‑compliant accuracy. The dirty cell is cleaned periodically according to site schedules.

Standards & Compliance
The sensor follows IEC 61724‑1 (Annex C). Clean‑cell calibration is performed under Class AAA solar simulator according to IEC 60904‑2 and IEC 60904‑4; reference cells are calibrated by recognized institutes (ISFH, Fraunhofer ISE).

Typical Delivery & Warranty

• Delivery times: small orders approx. 2–3 weeks; bulk orders (100 pcs) approx. 8–10 weeks.
• Warranty: 2‑year warranty against manufacturer defects.

Technical specifications

• Item Code: 3S‑SMS‑MB‑M
• Soiling Ratio: 0% – 100%
• Resolution: 0.1%
• Uncertainty: ≤1%
• Irradiance: 0…1600 W/m²
• Standard: IEC61724‑1 (Annex C)
• Data Output: RS485 up to 38400 Baud
• Communication Protocol: Modbus RTU
• Output Rate: 1/s
• Operating Temperature Range: -40°C to +85°C
• Operating Humidity Range: 0 to 100%
• Power Supply: 12 to 30 V DC
• Power Consumption: 20 mA @ 24 V DC
• Electrical Connection: 3 m LIYYC11Y PUR cable, UV and weather resistant
• Galvanic Isolation: 1000 V between power supply and RS485 bus
• IP Rating: IP68
• Dimensions: 244 mm x 108 mm x 42 mm (W x L x H)
• Weight: 500 g
• Calibration: Each sensor calibrated under Class AAA solar simulator per IEC 60904‑2 using reference cell calibrated by ISFH (Germany)
• Test: Each sensor tested under natural sunlight using a calibrated reference cell from Fraunhofer ISE (Germany)