Davis 6490 Installation Manual
UV and Solar Radiation Sensors
For Vantage Pro® and Vantage Pro2™ Weather Stations
The Davis Instruments UV Sensor is a precision instrument that detects ultraviolet (UV) radiation at wavelengths of 290 to 390 nanometers. The spectral
response is closely matched to the Erythema Action
Spectrum, defined by McKinlay and Diffey (1987) and
internationally recognized as the radiation that is most
responsible for causing redness of the human skin.
The Davis Instruments Solar Radiation Sensor is a precision instrument that detects radiation at wavelengths
of 300 to 1100 nanometers. The spectral response of
the silicon photodiode detector is a good match to the
spectrum of solar irradiance.
Typically, users install both the Solar Radiation Sensor and the Davis UV Sensor. However, users may install only one of these sensors. Unless otherwise noted, instructions
in this manual apply to both sensors.
Individual specifications for each sensor are listed on the Davis Website at
http://www.davisnet.com/support/weather/ under the spec sheets link.
Note: Sunburn is not the only consequence of exposure to UV radiatio n. Skin cancer s, cat a ract s, and d am-
age to the immune system are caused by UV radiation. Exposure to UV radiation should be minimized.
The UV Sensor is comprised of the following components:
Shield—The outer shell shields the sensor body from thermal radiation and provides a
path for convection cooling of the body , min imizing heating of the sensor interior. It
provides a cutoff ring for cosine response, a level indicator, and fins to aid in aligning
the sensor with the sun’s rays.
Sensor Body—Houses the following components:
• Diffuser—Provides, with gasket, a weather-tight seal and excellent cosine response.
• Filter—Provides the Erythema Action spectral response. Encased in multiple hard-
oxide coatings, the filter is stable in the presence of heat and humidity.
• Detector—Contains a semiconductor diode that, with the filter, responds to radia-
tion only in the specified wavelengths.
• Amplifier—Converts the detector current into a 0 to +2.5V signal.
The Solar Radiation Sensor is comprised of the following components:
Shield —Serves the same role as in the UV Sensor.
Sensor Body —Composed of a shield, the same as that in the UV Sensor; and a sensor
body, which contains a precision machined dif fuser giving excellent co sine response; a
hermetically sealed silicon photodiode; and an amplifier.
Products #6450 and #6490
Mounting Hardware
Please make sure you have all components
listed below before continuing.
• Shield
• Body with cable attached
• Three #6-32 x 1-1/2" (38 mm) machine
screws
• Three springs
• Three #6 flat washers
• Three #6 screw retainers
Tools and Materials Needed
To install your new sensor, you will need a medium Phillips screwdriver.
Mounting the Sensors
Installation on the Sensor Mounting Shelf
The Solar Radiation and UV Sensors are designed to be mounted on the Sensor Mounting Shelf (Davis Instruments Product Number 6672). The Sensor Mounting Shelf is a
stand that attaches to your ISS and provides a mounting location for up to two sensors.
First mount the shelf on the ISS and then follow these instructions to mount a UV or
Solar Radiation Sensor on the shelf. The shelf has two mounting locations, one to hold
a UV sensor and a the other for a Solar Radiation Sensor. Because they are identical, it
doesn’t matter which location you use first.
Testing the Sensor
On the Integrated Sensor Suite (ISS), the connections for the Solar Radiation and UV
sensors are inside the Sensor Interface Module (SIM) Box. Before permanently installing your new sensor, Davis Instruments recommends that you test it first. To do this,
take your console with you out to your ISS, and follow the instructions below.
Accessing the SIM
To access the SIM on a Vantag e Pro2 station, open the SIM Box. See Opening the SIM
Box in the Vantage Pro2 ISS Installation Manual for more information. On earlier Van-
tage Pro stations, the SIM Box is located below the ISS Radiation Shield. For instructions on how to access the SIM Box on these stations, see Opening the SIM Box in the
Vantage Pro ISS Installation Instructions. On Fan Aspirated Vantage Pro and Vantage
Pro2 stations, the SIM is located in a separate housing. Again, consu lt your ISS instruction manual for detailed instructions on how to access your SIM.
1. Plug the sensor cable into the receptacle labeled “UV” on the SIM if it is a UV
sensor or into the receptacle labeled “SUN” if it is a Solar Radiation Sensor.
Hold the sensor body with the white diffuser pointed upward. Do not touch the diffuser. If you do, clean it after mounting using a cotton swab and ethyl alcohol. Do
not use rubbing alcohol.
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