SR15 Digital "First Class" Pyranometers with various outputs

The new SR15 digital high-accuracy pyranometer series is "First Class" according to the ISO 9060:1990 standard and "Spectrally Flat Class B" in the ISO 9060:2018 revision.
With their on-board heaters, SR15-D1 and the analogue SR15-A1 are the only first class sensors compliant with the requirements for Class B PV monitoring systems of the IEC 61724-1:2017 standard without the need for energy-hungry accessories.

Measures: hemispherical solar radiation
ISO classification: first class pyranometer; spectrally flat class B pyranometer (2018)
IEC 61724-1 compliance: meets Class B PV monitoring system requirements
Calibration uncertainty: < 1.8 % (k = 2)
Calibration traceability: to WRR
Spectral range: 285 to 3000 x 10-9 m
Sensitivity (nominal): 10 x 10-6 V/(W/m2)
Analogue output: millivolt
Response time: < 10 s
Zero offset a: 5 W/m2 unventilated
Rated operating temperature range: -40 to +80 °C
Temperature response: < ± 2 % (-10 to +40 °C)
Heater: 1.5 W at 12 VDC
Standard cable length: 5 m
Levelling: optional spring-loaded levelling, with / without tube mount

Output:
Version SR15-D1
Communication protocol: Modbus over 2-wire RS-485
Transmission mode:   RTU
Output:
    - irradiance in W/m2
    - instrument body temperature in °C
On-board heater:    included
Version SR15-D2A2
Communication protocol:   Modbus over TTL
Transmission mode:    RTU
Output
    - irradiance in W/m2
    - instrument body temperature in °C
On-board heater:    not included
Analogue output:    4-20 mA current loop

For 4-20 mA output use model:
SR15-D2A2-05 - Class B (first class) spectrally flat digital pyranometer, with Modbus over TTL and 4-20 mA output, with 5 m cable.