Pyrheliometer DR20-A1

Overview
The DR20-A1 is an analog, industrial-grade Class A pyrheliometer designed for high-accuracy measurement of Direct Normal Irradiance (DNI) in photovoltaic systems, solar resource assessment, and meteorological applications. Designed for operation on a two-axis solar tracker, the DR20-A1 combines excellent measurement accuracy with low-power window heating to provide reliable direct solar radiation measurements in all climatic conditions.

Key features
• Class A performance: fully compliant with ISO 9060 Class A specifications and WMO recommendations for high-accuracy direct solar radiation measurements.
• Measures Direct Normal Irradiance (DNI) with a 5° full field of view.
• Low-power heating system: requires only 1 W to keep the window free from dew and frost (4x increase in heating at same heating power compared to older models).
• Analog output for seamless integration with a wide range of data acquisition systems.
• Supplied with individual test reports including sensitivity, response time, and temperature response.

Applications
• Direct Normal Irradiance (DNI) monitoring for photovoltaic (PV) performance monitoring systems
• Solar resource assessment and meteorological monitoring networks.
• High-accuracy solar radiation monitoring in locations affected by dew and frost

Specifications
• Measurand: Direct Normal Irradiance (DNI) [W/m²]
• Sensor classification: ISO 9060 Class A pyrheliometer
• Calibration uncertainty: < ±1.2%
• Field of view: 5°
• Response time (95%): 4 s
• Spectral range: 200 to 4000 nm
• Tilt measurement uncertainty: ±1° (0 to 180°)
• Power consumption with heater on: 1W
• Operating temperature range: -40 °C to +80 °C
• Temperature response (-10 °C to +40 °C): < ±0.5%
• Temperature response with correction in data processing (-30 to +50 °C): < ±0.4%
• Standard cable length: 5 m

Cable length options
• 5 m