SQ-521-SS SDI-12 Digital Output Full-spectrum Quantum Sensor

The SQ-521 is a digital sensor with SDI-12 communication protocol.

  • Product Name:SDI-12 Digital Output Full-spectrum Quantum Sensor
  • Item No.:SQ-521-SS
  • Manufacturers:Apogee
  • Country of Origin:USA

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. 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. Quantum sensors are also used to measure PAR/PPFD in aquatic environments, including salt water aquariums where corals are grown.

Input Voltage Requirement    4.5 to 24 V DC

Current Drain    0.6 mA (quiescent), 1.3 mA (active)

Calibration Uncertainty    ± 5 %

Measurement Repeatability    Less than 1 % (up to 4000 µmol mˉ² sˉ¹>)

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

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

Response Time    0.6 s, time for detector signal to reach 95 % following a step change, fastest data transmission rate for SDI-12 circuitry is 1 s

Field of View    180 ˚

Spectral Range    389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)

Spectral Selectivity    Less than 10 % from 412 to 682 nm ± 5 nm

Directional (Cosine) Response    ± 2 % at 45 ˚, ± 5 % at 75 ˚

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 %

Detector    Blue-enhanced silicon photodiode

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    45 mm height, 23.5 mm diameter

Mass    100 g

Cable    5 m of two conductor, shielded, twisted-pair wire; additional cable available in multiples of 5 m; santoprene rubber jacket; pigtail lead wires