Dragino WSS-27, PAR sensor 400 to 700 nm, RS485

The Dragino WSS-27 measures the photosynthetically active radiation (PAR) of daylight in the wavelength range from 400 to 700 nm, which is precisely the portion of sunlight that plants use for photosynthesis. A precise optical detector with an upstream 400 to 700 nm filter provides a signal proportional to the incident radiation, with the measurement following the cosine of the angle of incidence. The sensor communicates via RS485 and is designed as an expansion sensor for the Dragino WSC2-L weather station.

Main features:

• Measurement of photosynthetic photon flux density (PPFD) in µmol/(m²·s), measuring range 0 to 2500 µmol/(m²·s)
  
• Spectrally limited to 400 to 700 nm by an optical filter in front of the detector
  
• RS485 interface with Modbus command set, can be operated directly on the WSC2-L main unit (standard baud rate 4800)
  
• Wide supply range from 5 to 24 V DC with low power consumption
  
• High long-term stability with an annual drift of a maximum of ±2 %
  

Specifications:

• Supply voltage: 5 to 24 V DC
  
• Interface: RS485
  
• Standard baud rate (with WSC2-L): 4800
  
• Spectral range: 400 to 700 nm
  
• Measuring range: 0 to 2500 µmol/(m²·s)
  
• Resolution: 1 µmol/(m²·s)
  
• Accuracy: ±2 %
  
• Long-term stability: ≤ ±2 % per year
  
• Current consumption: 5 mA at 12 V, 6 mA at 5 V
  
• Response time: 5 s
  
• Operating temperature: -30 °C to +75 °C
  
• Operating humidity: 10 to 90 % RH
  
• Dimensions: 15 × 11 × 6 cm
  
• Weight: 338 g

Application areas:

• Agricultural weather stations based on the Dragino WSC2-L for recording plant-available light
  
• Greenhouses to control supplemental lighting or shading based on natural PAR input
  
• Plant cultivation and variety trials with determination of the Daily Light Integral (DLI) from PAR readings
  
• Forestry, ecology, and vegetation monitoring, e.g., light conditions under tree canopies or in canopy gaps

Documents:

• User Manual