ePAR Sensor Sensor 400-750 nm SDI-12

In stock (can be backordered)


In stock (can be backordered)

SKU: SN-SQ-617-SS Categories: , , , Tags: , , , ,


Apogee’s SN-SQ-617-SS cutting-edge ePAR sensor id designed to measure the newly defined 400-750 nm ePAR radiation range that research has shown to be photosynthetically active, beyond the traditional 400-700 nm range. The SN-SQ-617-SS ePAR is a digital sensor with SDI-12 communication protocol. The sensor features a rugged, aluminum housing that is fully-submersible and built to withstand harsh conditions, and high-quality cable terminating in pre-tinned pigtail leads for easy connection to dataloggers and controllers. The sensor cable includes an IP68 marine-grade stainless-steel cable connector to simplify sensor removal and replacement from permanent installations for maintenance and calibration. Typical applications of ePAR sensors include measuring total ePAR intensity over plant canopies in all growing environments, monitoring and adjusting grow lights, and researching plant morphogenic activity and photobiology. Many next generation LED fixtures, the sun, and other light sources emit these newly confirmed Far-red photosynthetic wavelengths, but they have not been measurable by traditional 400-700 nm PAR meters until now.

Spectral Response

Apogee’s The ePAR sensor has a spectral range of 400 to 750 nm ± 5 nm. The spectral response can be seen in the graph below.

SN-SQ-647-SS Spectal Response

SN-SQ-647-SS Spectal Response

Rugged, Self-cleaning Housing

Apogee’s Patented domed shaped sensor head (diffuser and body) facilitate runoff of dew and rain to keep the sensor clean and minimize errors caused by dust blocking the radiation path. Sensors are housed in a rugged anodized aluminum body and electronics are fully potted.

Accurate, Stable Measurements

Sensors are cosine-corrected to maintain their accuracy when radiation comes from low zenith angles. The sensors measure PPFD with a cosine response accurate within ± 5 % at 75° zenith angle. Long-term non-stability determined from multiple replicate quantum sensors in accelerated aging test and field conditions is less than 2 % per year.

Typical Applications

Apogee’s total ePAR intensity measurements over plant canopies in all growing environments, monitor and adjust grow lights, research plant morphogenic activity, and photobiology studies.


To ensure accuracy each sensor is carefully calibrated in controlled conditions and traceable to NIST reference standards. The Original sensors are pre-calibrated for either sunlight or electric light sources.

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