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SQ-647-SS SDI-12 Quantum Light Pollution Sensor

Updated:2025-03-13

Brand: Apogee
Model: SQ-647-SS
Description: The SQ-647 Quantum Light Pollution 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 conditi
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Product Details

Overview of SQ-647-SS SDI-12 Quantum Light Pollution Sensor：

User's Manual

The SQ-647 Quantum Light Pollution 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 Quantum Light Pollution 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 Quantum Light Pollution 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-647 sensors in indoor grow environments utilizing LED lights.

The analog version of this sensor (SQ-640) 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.

SQ-647-SS Sensor Drawing：

Specifications of SQ-647-SS:

Input Voltage	5.5 to 24 V DC
Current Draw	1.4 mA (quiescent), 1.8 mA (active)
Calibration Uncertainty	± 5 %
Measurement Range	0 to 200 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 200 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 %)
Directional (Cosine) Response	± 2 % at 45° zenith angle, ± 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 (with 5 m of cable)	140 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
Manufactured	Made in the USA