Diffuse solar radiation sensor SRD100

RS485Modbus RTUwith humidity measurement

Overview
The SRD100 is an industrial diffusometer for accurate measurement of diffuse solar radiation, intended for PV performance monitoring and meteorological applications. It is an all-digital, heated sensor that can be used standalone or together with a pyranometer to separate direct and diffuse irradiance components.

Key features

• No moving parts: static sensor array with a half-sphere shadow mask using a Fibonacci lattice for consistent diffuse measurement.
• IEC 61724-1 Class A compliance: designed to meet high-accuracy PV monitoring requirements.
• Digital connectivity: Modbus RTU over an isolated RS-485 interface for remote integration and diagnostics.
• Built-in heating: reduces dew and frost for reliable operation across climates.
• Spectrally matched: sensor response matched to silicon PV modules for PV-usable spectral irradiance measurement.
• Rugged surge protection: integrated surge immunity ±1 kV; optional SPD01 upgrade to 4 kV.
• Industrial design: IP67 ingress protection and industrial EMC performance suitable for outdoor PV plants.

Available options
Cable length

• No cable
• 3 m (9.8 ft)
• 5 m (16.4 ft)
• 10 m (32.8 ft)
• 20 m (65.6 ft)
• 30 m (98.4 ft)
• 50 m (164 ft)
• 70 m (229 ft)
• 100 m (328 ft)
• 130 m (426 ft)

Mounting hardware

• AMF03 - Albedometer mounting plate for 2 pyranometers (one up, one down for albedo)
• PMF01 - GHI mounting plate for 1-2.3 inch crossarms
• TLM01 - Ball leveling mount for 1-1.57 inch crossarms

Surge protection

• No Surge Protection
• SurgeSplitter - Industrial surge protection device for up to 2 pyranometers

Technical specifications

• Brand: Hukx
• Category: Diffusometers (diffuse radiation sensors)
• Intended use: Industrial diffusometer / monitoring applications
• Model: SRD100
• Configurable options: selectable cable lengths, mounting hardware, surge protection options (see lists above)
• Measurand: diffuse solar radiation [W/m²]
• Optional measurand: spectrally matched diffuse solar irradiance [W/m²]
• Spectral response: matched to silicon PV modules
• IEC 61724-1:2021 compliance: meets Class A PV monitoring system requirements for diffuse solar irradiance
• Instrument diagnostics: heating, internal humidity
• Heating: included
• Calibration certificate: included
• Standard cable length: 3 m
• Uncertainty of calibration: < ± 10 %
• Temperature response: < ± 0.4 % (‑30 to +50 °C)
• Rated operating temperature range: ‑40 °C to +80 °C
• Ingress protection: IP67
• Power consumption (heated): < 2 W (adjustable)
• Power consumption (unheated): < 0.5 W
• EMC / surge immunity: Equipment classification: Industrial Equipment; surge immunity Level 2 (test level 1 kV); with optional SPD01: Level 4 (test level 4 kV)
• Electrical safety compliance: EU Low Voltage Directive (2014/35/EU), USA National Electric Code (NFPA70)
• Earthing terminal: included on instrument
• Digital communication: Modbus RTU over 2-wire RS-485
• RS-485 isolation voltage: 1.5 kV