Quantum PAR Sensor

Measure Photosynthetically Active Radiation

The SQ-521 is a digital sensor with SDI-12 communication protocol. The sensor incorporates a rugged, self-cleaning sensor housing design, anodized aluminum body with acrylic diffuser, and high-quality cable terminating in a 3.5mm stereo jack for easy connection to METER dataloggers. Typical applications include PPFD measurement over plant canopies in outdoor environments, greenhouses, and growth chambers, and reflected or under-canopy (transmitted) PPFD measurements in the same environments.

Specteral Range
389 to 692 nm
Accuracy ± 5nm
Directional (cosine)
± 2 % at 45°, ± 5 % at 75° zenith angle
Response Time Less than 1 ms
Long-term Drift Less than 2 % per year
Calibrations and Conversions Sensors are calibrated for outside use
5.0 µmol m-2 s-1 per mV
Power None, self powered
Operating Environment -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m
Cable Length 5 m
Cable connector Types 3.5 mm "stereo" plug
Sensor Dimensions 30.5 mm diameter, 37 mm height
Data Logger Compatibility (not exclusive) ZL6 & ProCheck
Warranty One year, parts and labour

We periodically send an email newsletter containing updates, new product releases, training and advice. If you would like to receive these please subscribe below.


Labcell Limited exclusively supply and support METER products in the UK & Ireland.

Non UK/Ireland Customers, please contact METER Environment at:www.metergroup.com/environment/


METER Climate monitoring
Size: 1.9 MB (2,005,664 bytes)

Quotation Request

Email us to request a quotation for the Quantum PAR Sensor