SQ-620-SS 340-1040 nm Extended Range PFD Sensor

Apogee Instruments

SQ-620-SS 340-1040 nm Extended Range PFD Sensor

  • Vendor:Apogee

Availability: In Stock
$616.00
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Buy 1 $643.00 ea
Buy 10 $610.85 ea

The SQ-620 Extended Range PFD sensor is a self-powered sensor. 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 Extended Range PFD sensors include incoming PFD measurements over plant canopies in indoor greenhouses or in growth chambers, and reflected or under-canopy (transmitted) PFD measurements in the same environments. Since the detector on this particular Extended Range sensor is sensitive to radiation with wavelengths up to 1100 nm, beyond the range of wavelengths that influence plants, we recommend only using the SQ-620 sensors in indoor grow environments utilizing LED lights.

The analog version of this sensor (SQ-620) comes with the inline cable connector placed 30 cm from the sensor head for either standard use as a long-cable pigtail sensor, or for use with our microCache Bluetooth Micro Logger by unscrewing the connector, discarding the long section of cable and then screwing the sensor to the mating connector on the microCache.

How is the MQ-500 different from previous Apogee quantum sensors?

The SQ-620 is an extended range photon flux density (PFD) sensor with a spectral range of 340 to 1040 nm ± 5 nm, which can be seen in the graph below.


The MQ-500 is used to measure incoming PPFD measurements in outdoor environments, greenhouses, growth chambers, and aquariums.

MQ-620 Spectral Response

Where is the SQ-620 used?

The SQ-620 is used for measuring the newest generation of LED grow lights with wavelengths outside the traditional 400-700 nm PAR range. Research has shown the value of adding UV and far-red LEDs to fixtures to achieve various disease control and photomorphogenic effects. The extended range filter of the SQ-620 allows it to measure photons from UV and Far-red. The 1040 nm top cutoff also means the sensor will measure spikes in HID and other broad spectrum lights above the range that influences plants therefore the sensor is only intended for use in LED grow environments.


Power Supply: Self-powered

Sensitivity: 0.05 mV per µmol mˉ² sˉ¹

Calibration Factor: 20 µmol mˉ² sˉ¹ per mV

Calibration Uncertainty: ± 5 %

Measurement Range: 0 to 4000 µmol mˉ² sˉ¹

Measurement Repeatability: Less than 0.5 %

Calibrated Output Range: 0 to 200 mV

Long-term Drift (Non-stability): Less than 2 % per year

Non-linearity: Less than 1 % (up to 4000 µmol mˉ² sˉ¹)

Response Time: Less than 1 ms

Field of View: 180˚

Spectral Range: 340 to 1040 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)

Directional (Cosine) Response: ± 2 % at 45˚; ± 5 % at 75˚ zenith angle

Azimuth Error: Less than 0.5 %

Tilt Error: Less than 0.5 %

Temperature Response: -0.11 ± 0.04 % per C

Uncertainty in Daily Total: Less than 5 %

Housing: Anodized aluminum body with acrylic diffuser

IP Rating: IP68

Operating Environment: -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m

Dimensions: 30.5 mm diameter, 37 mm height

Mass: 51 g

Cable: 5 m of two conductor, shielded, twisted-pair wire; TPR jacket; pigtail lead wires; stainless steel (316), M8 connector located 25 cm from sensor head

Warranty: 4 years against defects in materials and workmanship