Light Measurement / Alat Pengukur Cahaya Dalam air[10 Mar. 2010, 22:33:43]
Keterangan
Applications :
Like all LI-COR instruments, the LI-250A is designed for
applications demanding performance, reliability and ruggedness.
The LI-250A provides direct digital readout of LI-COR
radiation sensors.
Photosynthetically Active Radiation ( PAR)
The LI-190SA Quantum Sensor is used by plant scientists,
horticulturists, and other environmental scientists to measure
Photosynthetic Photon Flux Density ( PPFD - the preferred
measurement of PAR) in natural sunlight, under plant
canopies, and in growth chambers and greenhouses.
The LI-190SA is also used in oceanography, limnology and
marine sciences as a reference sensor for comparison to
underwater PPFD measured by the LI-192SA Underwater
Quantum Sensor. The LI-250A can hold calibration multipliers
in memory for both a surface and underwater sensor.
Illuminance
For lighting studies or architectural modeling, the LI-250A
and LI-210SA Photometric Sensor provide a direct readout
of illuminance in lux. The LI-210SA measures visible radiation
and has a spectral response curve equal to that for the
average human eye. This curve is known as the CIE Standard
Observer Curve and is matched by the LI-210SA to
within 5% under most light sources.
Solar Irradiance
Solar irradiance measurements for meteorological, hydrological
and environmental research can be made using the
LI-200SA Pyranometer Sensor. The LI-200SA measures
global solar radiation ( sun plus sky) and provides a typical
accuracy of ± 5% under unobstructed daylight conditions.
Sensor Compatibility
Type " SA" sensors ( e.g. LI-190SA) are recommended for use
with the LI-250A. Older type " SB" sensors ( e.g. LI-190SB)
can also be used by removing the calibration connector.
Other types of older LI-COR sensors can be made compatible
by adding a BNC connector to the cable.
Specification :
Accuracy:
25 ° C: Typically ± 0.4% of reading ± 3 counts
on the least significant digit displayed
( all ranges) .
0 - 55 ° C: Typically ± 0.6% of reading ± 3 counts
on the least significant digit displayed
( all ranges) .
Range Selection: Autoranging ( 3 ranges) .
Linearity: ± 0.05% .
Sensors: Any LI-COR type " SA" or type " SBâ sensor with
BNC connector; Quantum, Pyranometer, or Photometric.
Older LI-COR radiation sensors, or those without any
connector must have a BNC connector installed. Contact
LI-COR.
Sensor Calibration: Each sensor is supplied with a calibration
multiplier. Calibration multipliers for two sensors can
be stored in memory. Calibration multipliers are entered
from the keypad.
Signal Averaging: Sensor output can be collected and displayed
as a 15-second average ( approximately 60 readings) .
Averages are retained on the display in HOLD mode.
Display: 4 1/ 2 digit LCD display. Updated every 0.5 seconds
in Instantaneous mode.
Keypad: Sealed, 5-key tactile response keypad.
Battery Life: 150 hours typical with continuous operation.
Power Requirement: One 9V Eveready Alkaline # 522 or
equivalent ( LI-COR part number 216) .
Low Battery Detection: Low battery indicator displayed
with approximately 20 hours battery life remaining.
Operating Conditions: 0 to 55 ° C, 0 to 95% RH
( non-condensing) .
Storage Conditions: -55 to 60 ° C, 0 to 95% RH
( non-condensing) .
Size: 14 cm L Ã 7.7 cm W Ã 3.8 cm D ( 5.5" Ã 3" Ã 1.5" ) .
Weight: 0.26 kg ( 0.57 lbs) .
Warranty: 1 year parts and labor.