LI-COR Sensors

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LI-COR radiation sensors receive radiation in a photodiode, which generates a small current in direct proportion to the incident light intensity. The response to light of different wavelenths is tailored by filters inside the different models of sensor to match the response of plants, the human eye, or pyranometry. The current produced by the sensor is too small for use with many data loggers and controllers. The EME Systems UCLC (Universal Current Loop Converter) or UTA (Universal Transconductance Amplifier) can be used to amplify the LI-COR signals to higher levels of voltage or current for use with standard data loggers and controllers.

Photo: A LI-COR terrrestrial sensor seated in a L2003S leveling fixture.   

EME Systems sells the following LI-COR radiation sensors and accessories:

LI190SZ or LI200SA

measuring units of PAR (photosynthetically active radiation) in units of micromoles per meter²second, for plant growth studies.

LI200SZ or LI200SA

measuring units of watts per meter², for general pyranometry, studies of energy transfer.

LI210SZ or LI210SA

measuring units of lux or footcandles, for illumination studies relevant to the human eye response.

 

L2003S

mounting and leveling fixture for the above terrestrial sensors

 

LI193SA, and other special sensors

underwater spherical quantum sensor. other specialized sensors, and cable, on special order.

 

• LI-COR sensor and accessory prices from EME Systems ««««

   

   

The suffix SZ or SA refer to the termination of the cable. These LI-COR sensors all have an RG174U coaxial cable either 10 or 50 feet long

-SZ

This is a bare wire termination for connection to screw-down terminals. The cable can pass through a gland nut into an enclosure for the best possible water resistance. This is the least expensive option

-SA

The coaxial cable is terminated with a BNC connector. This allows quick and easy connection to a mating BNC connector on an instrument enclosure. However, it is not waterproof, and it costs more than the SZ termination.

-SB

Not offered nor recommended by EME Systems. This is a special connector that contains a resistor that converts the tiny current produced by the sensor into a proportional voltage of between 5 and 10 millivolts full scale. This is subject to noise pickup. It is better to use the amplifiers.

-50

the sensors are in stock with 10 feet of cable, 50 feet on special order.

 

LI-190 Quantum Sensor This sensor has a response between 400 and 700 nm and fits the ideal quantum response closely. These are the wavelengths that drive photosynthesis (PAR-Photosynthetically Active Radiation). Integration of PAR closely approximates the potential for photosynthetic activity. These sensors are popular for studies of plant growth both in native environments and in greenhouses. They are not affected by the disproportionate amounts of infrared or yellow that can distort the results of plant growth studies based on pyranometers or photometers.

LI-200 Pyranometer Sensor This sensor has a spectral response curve that covers a wide range from 400 nm to 1100 nm with a peak in the infrared at 950 nm. The photodiode used in this sensor is blue-enhanced to increase its response at the shorter wavelenths. The pyranometer is suitable for measurements of global solar radiation in unobstructed daylight. It is used in many agricultural, meteorological and solar energy studies. The sensor is calabrated against an Eppley Precision Spectral Pyranometer under natural daylight to achieve a high correlation to the PSP measurements under those spectral conditions. Furthermore, the LI-200 operates on a silicon photovoltic detector which allows it to be priced much lower than thermopile-based pyronometers while producing great results.

LI-210 Photometric Sensor This sensor has a bell-shaped response between 400 and 700 nm with a peak at 550 nm. The response curve corresponds to the response of the average human eye (photopic curve) within 5% in most light sources. The LI-210 photometer has many applications in architecture (eg - workplace or room lighting studies), illumination engineering, biological sciences, etc.

Each of these sensors comes with inidividual calibration data. At a given light level, each sensor will have a slightly different output, The individual calibration multiplier is provided by LI-COR on a certificate that accompanies the instruction manual, and also on a tag affixed to the individual cable. It is necessary to enter the calibration multiplier into software (or the hardware equivalent, by adjusting the gain of an amplifier), in order to achieve accurate results.

light level = current * multiplier

Please refer to the manuals for the UTA and UCLC amplifiers for example calculations.

Spherical Underwater Quantum Sensors (pictured to the right) are also available from EME Systems. These devices gather photosynthetically active radiation from all directions for growth studies of underwater plant species. The response curve is the same as the LI190 Terrestrial Quantum PAR sensor described above.

If you would like to visit LI-COR's web site directly, click here...http://env.licor.com/

• LI-COR Prices