SPECIFICATIONS
Calibration Traceability
Apogee Instruments SQ-600 series PFD sensors are calibrated through side-by-side comparison to the mean of four
transfer standard PFD sensors under a reference lamp. The transfer standard PFD sensors are recalibrated with a
quartz halogen lamp traceable to the National Institute of Standards and Technology (NIST).
SQ-620-SS
Power Supply
Self-powered
Sensitivity
0.05 mV per µmol m
-2
s
-1
Calibration Factor
20 µmol m
-2
s
-1
per mV
Calibration Uncertainty
± 5 % (see Calibration Traceability below)
Measurement Range
0 to 4000 µmol m
-2
s
-1
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 m
-2
s
-1
)
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 %; see Spectral
Response below)
Directional (Cosine)
Response
± 2 % at 45° zenith angle, ± 5 % at 75° zenith angle (see Directional Response below)
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
