RS485 solar radiation sensor 3S-4IS

Modbus RTUwith mV outputfor meteorological data

Overview
The 3S-4IS Multi-Orientation Irradiance Sensor is designed for PV plants with three or four distinct orientations. It provides a single Total Compensated Effective Irradiance value and a Total Effective Module Temperature for the entire plant by weighting plane-of-array (POA) measurements according to the number of panels installed per orientation. Configuration is done via the 3S-4IS setup tool and results are transmitted over RS-485 Modbus RTU to support accurate Performance Ratio (PR) calculations.

How it works
Each irradiance sensor is installed in the same plane as the corresponding panels and measures POA irradiance and internal cell temperature per orientation. During commissioning the installer enters the panel count per direction into the electronic box; the box combines individual POA readings into one Total Compensated Effective Irradiance and computes the Total Effective Module Temperature. All per-orientation and total values are reported via RS-485 Modbus RTU to the datalogger for correct PR calculation at multi-orientation sites.

Typical measured / derived data

• POA irradiance and internal cell temperature for each orientation (up to 4 planes)
• Total Compensated Effective Irradiance (single plant input for PR)
• Module temperature per orientation (when module temp sensors are connected)
• Total Effective Module Temperature
• Ambient temperature
• Wind speed
• Wind direction

Key features

• Weighted effective irradiance for real plant layout: Combines per-orientation POA readings according to panel counts to produce a single irradiance input aligned with the actual array distribution.
• Straightforward commissioning: Enter panel counts per direction once using the configuration tool; no external averaging scripts required.
• Single communication line: All sensors report via one RS-485 Modbus RTU line, reducing wiring and Modbus node count.
• IEC-aligned performance: Designed to meet IEC 61724-1:2021 Class A requirements for PV monitoring.
• Alternative to separate site handling: Avoids treating each orientation as a separate site with separate dataloggers or inverters.

Technical specifications

• Item Code: 3S-4IS
• Electronic box - connected sensors: Four Irradiance Sensors (3S-IS-mV); Four Module Temperature Sensors (3S-MT-PT1000); Ambient Temperature Sensor (3S-AT-PT1000); Wind Speed Sensor (3S-WS-PLS); Wind Direction Sensor (3S-WD)
• Data output (electronic box): RS485 up to 38400 Baud
• Communication protocol: Modbus RTU
• Output rate: 1/s
• Operating temperature (electronic box): -40°C to +85°C
• Box material: ABS
• Box dimensions (L x W x H): 211 mm x 123 mm x 60 mm
• Box weight: 450 g
• Box IP rating: IP67
• Power supply: 12 to 30 V DC
• Power consumption: 40 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
• Irradiance sensor (3S-IS-mV) key specs:
  • Reference cell: Monocrystalline silicon (31 mm x 31 mm)
  • Current shunt: High-precision shunt resistor soldered to cell terminals
  • Irradiance range: 0–1600 W/m²
  • Uncertainty: ≤1% (≤2% as per IEC 61724-1 Class A)
  • Resolution: 0.1 W/m² (≤1 W/m² as per IEC 61724-1 Class A)
  • Response time: 1 s (≤3 s as per IEC 61724-1 Class A)
  • Drift: <0.3%/year
  • Field of view: >160° (IEC 61724-1 Class A)
  • Tilt-azimuthal angle: 0°-0°, ≤1° (IEC 61724-1 Class A)
  • Sensor output: mV signal
  • Cell temperature sensor: PT1000 Class A (EN 60751)
  • Sensor box dimensions (W x L x H): 140 mm x 110 mm x 42 mm
  • Sensor weight: 260 g
  • Sensor IP rating: IP54 (IP68 optional)
  • Sensor housing material: Aluminum
  • Standards: IEC 61724-1:2021 and IEC 60904
  • Calibration: Each sensor calibrated under Class AAA solar simulator per IEC 60904-2 and IEC 60904-4 using a reference cell calibrated by ISFH (Germany)