LI-191R Rod shaped photosynthetically active radiation sensorMeasuring PAR within a range of 1 meter is mainly used in environments with inconsistent spatial lighting, such as the interior of plant canopies. LI-191R can quickly and consistently measure diverse point data in environments such as under the canopy. The measurement result data is PPFD, measured in µ mol · s^-1·m^-2.

working principle
LI-191R uses a quartz rod under a diffuser, with a length of 1 meter, to sense light within a range of 1 meter and output a response signal to a silicon photodiode. Due to the fact that the diffuser of LI-191R is a continuous and complete component, its output signal integrates the lighting conditions of countless points within this 1-meter range, representing the average PAR within this 1-meter long range. The filter effectively blocks light above 700nm, which is crucial for studying illumination under vegetation, as infrared radiation under vegetation is relatively high compared to visible radiation. The unique design of LI-191R gives the sensor excellent quantum response, which is very close to the ideal value.

Main advantages

Induction wavelength is 400-700nm
The measurement result is the average value of photosynthetically active radiation within a range of 1 meter, which can minimize experimental errors

Single person can complete multiple measurements in a short amount of time

Upgraded waterproof performance, suitable for long-term outdoor placement

The National Ecological Observatory Network (NEON) in the United States^®)）Selected for integrating PAR measurements

Technical Specifications

Absolute calibration：± 10%
sensitivity：7µA / 1000 µmol·s^-1·m^-2(Typical)
Linear rateThe maximum deviation is 1% (10000 µ mol s)^-1m^-2Within)
response time：10 µs.
temperature-relatedNot exceeding ± 0.15%/℃
Cosine correctionAcrylic diffuser cosine correction
Azimuth errorAt a 45 ° elevation angle, the error within a 360 ° azimuth range is less than ± 2%
Sensitivity variation in length direction<± 7% (measured under a 2.54cm wide incandescent light source)
Sensing area：1m×12.7mm

working environment-40~65 ℃, 0~95% RH (non condensing)

detectorHigh stability silicon photovoltaic detector (blue light enhanced)
Sensor baseAnodized aluminum waterproof shell with acrylic diffuser, stainless steel screws
size：121.3 L×2.54 W×2.54 D cm
weight：1.4 kg
Cable length：2m, 5m



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Origin and Manufacturer: United StatesLI-CORcompany