The HMP50-ET is a temperature and relative humidity sensor manufactured by Vaisala. It measures air temperature with a 1000 ohm platinum resistance thermometer (PRT), and relative humidity with a capacitive chip. A radiation shield is used to cover the probe to protect it from sunlight.
- Measurement Range: -25° to +60°C
- Accuracy of +/- 0.8 º C
Relative Humidity
- Operating Range: 0 to 98% RH
- Accuracy: ±3% (0-90% RH); ±5% (90-98% RH)
Solar Radiation Sensor:
The CS305-ETM is a pyranometer manufactured by Apogee Instruments. It measures shortwave radiation using a silicon photovoltaic detector. The range of the sensor is 300 to 1100 nanometers, which encompasses most of the shortwave radiation that reaches the Earth’s surface.
Specifications:
- Accuracy: ±5% for daily total radiation
- Range: 0 to 2000 W m-2
- Operating Temperature: -40° to +55°C
- Relative Humidity: 0 to 100%
- Output of 0.2 mV per Wm-2
Rain Gage:
The TE525-ET tipping bucket rain gage is manufactured by Texas Electronics. It measures precipitation in 0.01 inch increments. The precipitation is funneled into a bucket that tips when filled to the calibrated level of 0.01 inches; the magnet connected to the tipping mechanism activates a switch as the bucket tips. This momentary switch closure is counted by the pulse-counting circuitry of the weather station’s data logger.
Specifications:
- Temperature: 0° to +50°C
- Resolution: 1 tip
- Rainfall per tip: 0.01” (0.254 mm)
- Orifice diameter: 6.06” (15.4 cm)
- Accuracy is ±1% at rates up to 1”/hr or +/- accuracy @ 2” per hr (50.8mm per hr) or less
Anemometer and Vane:
The 034B-ETM Windset is an instrument that combines a 3-cup anemometer and a wind vane. It is made of aluminum and its purpose is to measure wind speed and direction. The wind speed is measured as the cups rotate- opening and closing a reed switch at a rate corresponding to wind speed. The vane position is conveyed by a 10K ohm potentiometer with the output voltage related to wind direction.
Specifications
Anemometer
- Range: 0 to 110 mph (0 to 50 m/s)
- Threshold: 0.9 mph (0.4 m/s)
- Accuracy: ±0.25 mph (0.11 m/s) when less than 22.7 mph (10.1 m/s) or ±1.1% of true when greater than 22.7 mph (10.1 m/s)
Vane
- Mechanical range: 360°
- Electrical range: 356°
- Threshold: 0.9 mph (0.4 m/s)
- Accuracy: ±4°
- Damping ratio: 0.25
- Resolution: 0.5°
Solar Panel:
A 10-Watt solar panel powers the weather station, charging a 7-Ahr rechargeable battery.
Specifications
- Current at peak: 0.59 A
- Voltage at peak: 16.8 V
Datalogger:
An environmental enclosure (the white case) protects a CR1000M module and the battery. The datalogger is designed to both control the functions of the weather station instruments and record measurements. A spectrum spread radio then transmits the information to a nearby modem and is connected to the campus system.
Specifications:
- Analog inputs: 16 single-ended or 8 differential, individually configured
- Pulse counters: 2
- Switched voltage excitations: 3
- Control/digital ports: 8
- RS-232 port: 1
- CS I/O port: 1
- Scan rate: 100 Hz
- Burst mode: 1500 Hz
- Analog volt. resolution: to 0.33 uV
- A/D bits: 13
- Programming: CRBasic
- Data Storage: Table
- Telecommunications: PakBus
Works Cited
- Campbell Scientific. 2008. CR1000 Datalogger for Measurement and Control.
- Campbell Scientific. 2008. CS300-L Apogee PYR-P Pyranometer.
- Campbell Scientific. 2008. Evapotranspiration Monitoring Station Model ET107.
- Campbell Scientific. 2008. HMP50-L Vaisala Temperature and RH Sensor.
- Campbell Scientific. 2008. SP10 10-Watt Solar Panel.
- Campbell Scientific. 2008. TE525-L Texas Electronics 6” Rain Gage.
- Campbell Scientific. 2008. 034B-L Met One Windset.
- Campbell Scientific. 2008. 034B-L Met One Windset Instruction Manual.
- Campbell Scientific. 2008. 41303-5A 6- Plate Gill Radiation Shield.
- Retrieved 16 May 2008 from Campbell Scientific .
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