LI-COR LI-191R Line PAR Sensors
Features
- Spatially averages PPFD over its 1m length
- Uses a 1m quartz rod under a diffuser to conduct light to a single Quantum sensor
- Improved water resistance for long-term outdoor deployment
- Free ground shipping
- Expedited repair and warranty service
- Lifetime technical support
- More
Overview
The LI-191R Line Quantum Sensor measures Photosynthetically Active Radiation (PAR) integrated over its 1-meter length. It is used to measure sunlight under a plant canopy, where the light field is non-uniform. It measures light in units of Photosynthetic Photon Flux Density (PPFD), which is expressed as μmol s-1 m-2.
Mechanics
The entire LI‑191R diffuser is sensitive to light over its 1-meter length. Since the diffuser is one continuous piece, the LI‑191R essentially integrates an infinite number of points over its surface into a single value that represents light from the entire 1-meter length. The diffuser and single photodiode in the LI‑191R provide stable, integrated measurements that are superior to averages provided by many linear sensors. Optical filters block radiation with wavelengths beyond 700 nm, which is critical for under-canopy measurements, where the ratio of infrared to visible light may be high.
- Absolute Calibration: ± 10% traceable to National Institute of Science and Technology (NIST). The LI-191 is calibrated via transfer calibration
- Sensitivity: Typically 7 μA per 1,000 μmol s-1 m-2
- Linearity: Maximum deviation of 1% up to 10,000 μmol s-1 m-2
- Response Time: 10 μs
- Temperature Dependence: ± 0.15% per °C maximum
- Cosine Correction: Acrylic diffuser
- Azimuth: < ± 2% error over 360° at 45° elevation
- Sensitivity Variation over Length: ± 7% maximum using a 2.54 cm (1”) wide beam from an incandescent light source.
- Sensing Area: 1 m × 12.7 mm (39.4” × 0.50”)
- Detector: High stability silicon photovoltaic detector (blue enhanced)
- Sensor Housing: Weatherproof anodized aluminum housing with acrylic diffuser and stainless steel hardware.
- Size: 121.3 L × 2.54 W × 2.54 cm D (47.7” × 1.0” × 1.0”)
- Weight: 1.4 kg (3.0 lbs.)
- Cable Length: 2 m, 5 m (6.5', 16.4')
- (1) LI-191R Line PAR Sensor
- (1) Bubble level
- (1) Detachable 10 ft. cable
- (1) Hard-sided carrying case
Select Options
In The News
Water Conservation and Smart Growth in Texas
As states face annual droughts and water use continues to grow in order to meet population and production demands, water conservation is essential to protecting natural resources and long-term reliance. Over the years, conserving water has become more necessary as the world’s natural resources continue to be strained in order to meet needs. As a result, water conservation consultants have filled an essential niche in resource management. Eddie Wilcut, the Water & Energy Efficiency Practice Leader at Plummer , started his career in the Air Force, where he took some classes focusing on water resources. In those classes, Wilcut read Aldo Leopold’s “A Sand County Almanac,” and a specific line has stuck with him for the past 26 years.
Read More
It’s a Buoy! Highlighting the New NexSens XB-200 Data Buoy
As scientists seek to better understand aquatic ecosystems, utilizing small data buoys to monitor offshore and cover more water is becoming commonplace. The new NexSens Technology XB-200 data buoy was designed for inland and coastal monitoring applications. Although compact, the platform is designed with adequate space for multiple sensors and measurement electronics. When configured with the NexSens X3 data logger with IoT connectivity, internal batteries, solar panels, select sensors, and other accessories, the new buoy provides an off-the-shelf solution for any monitoring project. The new buoy concept was developed by the NexSens product development team with significant user input.
Read More
Predicting and Monitoring Ice Weather Events: The Great Lakes Approach to Ice Research
Ice cover on the Great Lakes provides numerous recreational and economic opportunities, including ice fishing, snowmobile charters, and ice caves on the lakes. Unfortunately, declining ice cover and increasing related weather events due to climate change, as well as other environmental stressors, have put such opportunities at risk. Historically, understanding winter weather has been difficult largely due to a lack of observations and, as a result, communities surrounding the Great Lakes have been left underprepared for extreme events.
Read More
