Campbell Met One 034A-L Manuel de l'opérateur télécharger pdf (Page 28)

Installation, Operation and Maintainance of Automatic Meteorological Stations

Sensors

Problem 3: Recorded wind directions exceed 360 degrees.

Remedy 3.1: Connect the CR10KD keyboard and use “star-six” mode to monitor the input locations. Check in

Annex 4 which one is used for Wind Direction and use the “A” key to advance to this location.

Manually rotate the wind vane to its maximum location; this is where the value on the keyboard jumps back

to zero. Write down the maximum wind direction (e.g. 367 degrees). Adjust the multiplier in the Wind Direction

Instruction in METSTAT by multiplying this value with 360 divided by the maximum wind direction. For this necessary

modification of METSTAT, the reader is referred to the Campbell Scientific Operators Manual for the CR10X Storage

and Control Module.

3.3 LI200X Pyranometer

3.3.1 General

Short wave solar radiation is an important parameter for determining potential and actual evaporation. It is used

both in the Penman-Monteith and Priestley-Taylor approach. The LI200X pyranometer measures both sun and sky

radiation on a horizontal surface. It uses a silicon photovoltaic cell mounted in a cosine-corrected head. The initial

current output of this sensor is transferred to voltage, which facilitates direct connection to the datalogger.

The technical specifications of this sensor are discussed in detail in the corresponding Campbell Scientific Instruc-

tion Manual for the LI200X pyranometer. The reader is referred to this text in case of need of more information.

3.3.2 Installation

Attach the 025 Pyranometer Cross Arm Stand to the 019 ALU Cross Arm. Figure 10 presents a graphical sketch of the set-up, as

well as some of the used terminology.

Figure 10: Installation of LI200 Pyranometer to Tripod

Fix the LI2003S base to the cross arm stand using the provided screws. Make sure the base is perfectly horizontal

by adapting the adjustment screws. Towards this end, the air bell of the built-in spirit level should be exactly located

in the middle of the circle on the glass.

Place the pyranometer in the base so that the cable fits into the slot. Tighten the pyranometer to the base plate

with the hex screw.

LI200X

LI2003S

025 Crossarm Stand

019ALU Crossarm

3/4"x3/4" NU-RAIL

Tripod Mast

1 2 ... 23 24 25 26 27 28 29 30 31 32 33 ... 74 75

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Campbell Met One 034A-L Manuel de l'opérateur Page 28