	MQ-510	SQ-520	MQ-210	SQ-420
Power Supply	-	Uses a 5 V USB power source and has a 2.1 mA current draw when logging	-	Uses a 5 V USB power source and has a 2.1 mA current draw when logging
Output Type	Meter	USB	Meter	USB
Resolution	-	0.1 µmol m^-2 s^-1	-	0.1 µmol m^-2 s^-1
Calibration Factor (reciprocal of sensitivity)	-	Custom for each sensor and stored in the firmware	-	Custom for each sensor and stored in the firmware
Calibration Uncertainty	± 5 %	± 5 %	± 5 %	± 5 %
Measurement Repeatability	Less than 0.5 %	Less than 0.5 %	Less than 0.5 %	Less than 0.5 %
Long-term Drift	Less than 2 % per year	Less than 2 % per year	Less than 2 % per year	Less than 2 % per year
Non-linearity	Less than 1 % (up to 4000 µmol m^-2 s^-1)	Less than 1 % (up to 4000 µmol m^-2 s^-1)	Less than 1 % (up to 4000 µmol m^-2 s^-1)	Less than 1 % (up to 4000 µmol m^-2 s^-1)
Response Time	Less than 1 ms	Software updates every second	Less than 1 ms	Software updates every second
Field of View	180°	180°	180°	180°
Spectral Range	389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)	389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 % of maximum)	410 to 655 nm (wavelengths where response is greater than 50 % of maximum)	410 to 655 nm (wavelengths where response is greater than 50 % of maximum)
Spectral Selectivity	Less than 10 % from 412 to 682 nm ± 5 nm	Less than 10 % from 412 to 682 nm ± 5 nm	Less than 10 % from 469 to 655 nm	Less than 10 % from 469 to 655 nm
Directional (Cosine) Response	± 5 % at 75° zenith angle	± 5 % at 75° zenith angle	± 5 % at 75° zenith angle	± 5 % at 75° zenith angle
Temperature Response	0.06 ± 0.06 % per C	0.06 ± 0.06 % per C	0.06 ± 0.06 % per C	0.06 ± 0.06 % per C
Operating Environment	0 to 50 C; less than 90 % non-condensing relative humidity up to 30 C; less than 70 % non-condensing relativity humidity from 30 to 50 C; separate sensors can be submerged in water up to depth of 30 m	-40 to 70 C, 0 to 100 % relative humidity, can be submerged in water up to depths of 30 m	0 to 50 C; less than 90 % non-condensing relative humidity up to 30 C; less than 70 % non-condensing relativity humidity from 30 to 50 C; separate sensors can be submerged in water up to depth of 30 m	-40 to 70 C, 0 to 100 % relative humidity, can be submerged in water up to depths of 30 m
Sensor Dimensions	24 mm diameter, 37 mm height	24 mm diameter, 37 mm height	24 mm diameter, 28 mm height	24 mm diameter, 28 mm height
Meter Dimensions	126 mm length, 70 mm width, 24 mm height	-	126 mm length, 70 mm width, 24 mm height	-
Mass (with 5 m of cable)	100 g	100 g	90 g	90 g

Power Supply

Uses a 5 V USB power source and has a 2.1 mA current draw when logging

Output Type

Meter

USB

Meter

USB

Resolution

0.1 µmol m^-2 s^-1

Calibration Factor (reciprocal of sensitivity)

Custom for each sensor and stored in the firmware

Calibration Uncertainty

± 5 %

Measurement Repeatability

Less than 0.5 %

Long-term Drift

Less than 2 % per year

Non-linearity

Less than 1 % (up to 4000 µmol m^-2 s^-1)

Response Time

Less than 1 ms

Software updates every second

Less than 1 ms

Software updates every second

Field of View

180°

Spectral Range

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

410 to 655 nm (wavelengths where response is greater than 50 % of maximum)

Spectral Selectivity

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

Less than 10 % from 469 to 655 nm

Directional (Cosine) Response

± 5 % at 75° zenith angle

Temperature Response

0.06 ± 0.06 % per C

Operating Environment

0 to 50 C; less than 90 % non-condensing relative humidity up to 30 C; less than 70 % non-condensing relativity humidity from 30 to 50 C; separate sensors can be submerged in water up to depth of 30 m

-40 to 70 C, 0 to 100 % relative humidity, can be submerged in water up to depths of 30 m

Sensor Dimensions

24 mm diameter, 37 mm height

24 mm diameter, 28 mm height

Meter Dimensions

126 mm length, 70 mm width, 24 mm height

Mass (with 5 m of cable)

100 g

90 g