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SQ-618-SS Modbus Digital Output 400-750 nm ePAR Sensor

Updated:2025-03-13

Brand: Apogee
Model: SQ-618-SS
Description: Apogee's newest, cutting-edge ePAR sensor was created in 2021 as an upgrade to our ePFD sensor and designed to measure the newly defined 400 -750 nm ePAR radiation range that research has shown to be.
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Product Details

Overview of SQ-618-SS Modbus Digital Output 400-750 nm ePAR Sensor：

User's Manual

Apogee's newest, cutting-edge ePAR sensor was created in 2021 as an upgrade to our ePFD sensor and 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 SQ-618-SS ePAR sensor outputs a digital signal using Modbus RTU protocol over RS-232 or RS-485. 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 UV and Far-red photosynthetic wavelengths, but they have not been measurable by traditional 400-700 nm PAR meters until now.

The analog version of this sensor (SQ-610) 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-618-SS Sensor Drawing：

Specifications of SQ-618-SS:

Input Voltage Requirement	5.5 to 24 V DC
Average Max Current Draw	RS-232 37 mA; RS-485 quiescent 37 mA, active 42 mA
Calibration Uncertainty	± 5 %
Measurement Repeatability	Less than 1 %
Long-term Drift	Less than 2 % per year
Non-linearity	Less than 1% (up to 4000 μmol mˉ2 sˉ1)
Spectral Range	400 to 750 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)
Directional (cosine) Response	± 2 % at 45?, ± 5 % at 75? zenith angle
Temperature Response	-0.11 ± 0.04 % per C
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 (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
Warranty	4 years against defects in materials and workmanship
Manufactured	Made in the USA