Sensor Calibration
Apogee SQ-620 Extended Range PFD Sensors have standard calibration factors of exactly:
20 µmol m
-2
s
-1
per mV
Multiply the calibration factor by the measured mV signal to convert sensor output to photon flux density in units
of µmol m
-2
s
-1
:
Calibration Factor (20 µmol m
-2
s
-1
per mV) * Sensor Output Signal (mV) = Photon Flux Density (µmol m
-2
s
-1
)
20 * 50
= 1000
Example of photon flux density measurement with an
Apogee model SQ-620 Extended Range PFD Sensor. The
LED in this example Full yields a photon flux density on a
horizontal plane of 1000 µmol m
-2
s
-1
. This yields an output
signal of 50 mV. This signal is converted to photon flux
density by multiplying by the calibration factor of 20
mol
m
-2
s
-1
/ mV.
LED Output
(1000 µmol m
-2
s
-1
)
Sensor Output
50 mV
