SMP21

The SMP21 is a secondary standard pyranometer that combines the sensor technology from the CMP21, has the RS-485 Modbus® interface, analogue output, low maintenance and 5 year warranty (*).

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Key features

RS-485 Modbus® communication
No change of desiccant for 10 years
5 year warranty (*)

The SMP21 has an internal desiccant that will last for at least 10 years. This minimises maintenance significantly. The interval for dome cleaning can be extended, and the quality of measurements maximised, by fitting SMP21 with the CVF4 ventilation unit.

The SMP21 has Modbus® RTU interface, amplified analogue output, improved response time and individual temperature corrected measurement data. The SMP21 is supplied with individual measured cosine response data. The wide and low power supply range from 5 to 30 VDC makes integration in meteorological and solar energy stations easy. The SMP21 is protected against over voltage, reversed polarity and short circuiting.

Thanks to standardised output and connections of every SMP6, exchanging instruments for recalibration is easy. SmartExplorer Windows™ software for data logging, display of data and Modbus® address setting is provided as standard.

(*) This product will need to be registered by the end-user within 6 months of purchase to activate the warranty extension.

Technical specification

Spectral range (20% point)	280 to 3000 nm
Spectral range (50% points)	285 to 2800 nm
Response time (63%)	< 0.7 s
Response time (95%)	< 2 s
Zero offset A	< 7 W/m²
Zero offset B	< 2 W/m²
Temperature dependence of sensitivity (-20 ºC to +50 ºC)	< 0.5 %
Temperature dependence of sensitivity (-40 °C to +70 °C)	< 1 %
Analogue output (-A / -V version)	4 to 20 mA / 0 to 1 V
Digital output	2-wire RS-485