	S2-131-SS*	S2-431-SS	S2-432-SS
Power Supply	Self-powered	5.5 to 24 V DC	5.5 to 24 V DC
Current Draw	-	1.4 mA (quiescent), 1.8 mA (active)	RS-232 37 mA; RS-485 quiescent 37 mA, active 42 mA
Output (Sensitivity)	0.08 mV per µmol m^-2 s^-1 (typical value, variable from sensor to sensor)	-	-
Calibration Factor (reciprocal of sensitivity)	12 µmol m^-2 s^-1 per mv (typical value, variable from sensor to sensor)	Custom for each sensor and stored in firmware	Custom for each sensor and stored in firmware
Calibration Uncertainty	± 5 %	± 5 %	± 5 %
Output Range	0 to 33 mV	SDI-12	Modbus
Wavelength Ranges	645 to 665 nm ± 5 nm (Red) 720 to 740 nm ± 5 nm (Far-Red)	645 to 665 nm ± 5 nm (Red) 720 to 740 nm ± 5 nm (Far-Red)	645 to 665 nm ± 5 nm (Red) 720 to 740 nm ± 5 nm (Far-Red)
Measurement Range	0 to 400 µmol m^-2 s^-1	0 to 400 µmol m^-2 s^-1	0 to 400 µmol m^-2 s^-1
Measurement Repeatability	Less than 1 %	Less than 1 %	Less than 1 %
Long-term Drift	Less than 2 % per year	Less than 2 % per year	Less than 2 % per year
Response Time	Less than 1 ms	Less than 0.6 s	-
Non-linearity	Less than 1 % (up to 400 µmol m^-2 s^-1)	Less than 1 % (up to 400 µmol m^-2 s^-1)	Less than 1 % (up to 400 µmol m^-2 s^-1)
Field of View	180°	180°	180°
Directional (Cosine) Response	± 2 % at 45°; ± 5 % at 75° zenith angle	± 2 % at 45°; ± 5 % at 75° zenith angle	± 2 % at 45°; ± 5 % at 75° zenith angle
Temperature Response	Less than 0.1 % per C	Less than 0.1 % per C	Less than 0.1 % per C
Housing	Anodized aluminum body with acrylic diffuser	Anodized aluminum body with acrylic diffuser	Anodized aluminum body with acrylic diffuser
IP Rating	IP68	IP68	IP68
Operating Environment	-40 to 70 C; 0 to 100 % relative humidity	-40 to 70 C; 0 to 100 % relative humidity	-40 to 70 C; 0 to 100 % relative humidity
Dimensions	30.5 mm diameter, 37 mm height	30.5 mm diameter, 37 mm height	30.5 mm diameter, 37 mm height
Mass (with 5 m of cable)	140 g	140 g	140 g
Cable	5 m of shielded, twisted-pair wire with TPR jacket and stainless steel connector	5 m of shielded, twisted-pair wire with TPR jacket and stainless steel connector	5 m of shielded, twisted-pair wire with TPR jacket and stainless steel connector

Power Supply

Self-powered

5.5 to 24 V DC

Current Draw

1.4 mA (quiescent), 1.8 mA (active)

RS-232 37 mA;
RS-485 quiescent 37 mA, active 42 mA

Output (Sensitivity)

0.08 mV per µmol m^-2 s^-1 (typical value, variable from sensor to sensor)

Calibration Factor (reciprocal of sensitivity)

12 µmol m^-2 s^-1 per mv (typical value, variable from sensor to sensor)

Custom for each sensor and stored in firmware

Calibration Uncertainty