Vantage Pro2 Weather Envoy Manual

Vantage Pro2 Weather Envoy Manual
Vantage Pro2™
Weather Envoy Manual
For Vantage Pro2™ & Vantage Pro2 Plus™ Weather Stations
Davis Instruments, 3465 Diablo Avenue, Hayward, CA 94545 • 510-732-9229 •
FCC Part 15 Class B Registration Warning
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules.
These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment
generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause
harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment on and off, the user is encouraged to try to correct the interference by one or more of the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
Changes or modification not expressly approved in writing by Davis Instruments may void the warranty and void the user's authority to
operate this equipment.
IC: 378810-6312
EC EMC Compliance
This product complies with the essential protection requirements of the EC EMC Directive 89/336/EC.
Weather Envoy for Vantage Pro2 Manual
Rev. A, December 7, 2004
Document Part Number: 07395.281
For Vantage Pro2 Weather Envoys # 6316 & 6316C
Vantage Pro and Vantage Pro2 are trademarks of Davis Instruments Corp., Hayward, CA.
© Davis Instruments Corp. 2004. All rights reserved.
Information in this document subject to change without notice.
3465 Diablo Avenue, Haywa rd, CA 94545-2778
510-732-9229 ¥ Fax: 510-732-9188
E-mail: ¥ www
Welcome to the Weather Envoy!
Welcome to Davis Instruments’ Weather
Envoy®! The Weather Envoy provides a
new and exciting way of getting weather
data from your Vantage Pro2™ weather station and into your Windows (95 or later) or
Macintosh (OS X) computer.
The Weather Envoy® includes the data collection and logging functions of the Vantage Pro2™ Envoy, but in a smaller
package that can be discreetly placed next to your computer. Both cabled and
wireless versions of the Weather Envoy are available. In combination with our
WeatherLink software, the Weather Envoy allows you to view, store, plot, analyze, export, share, and print your weather data.
Before continuing, please be sure your Weather Envoy package includes the
Envoy console
Two #6 x 1” screws for wall mounting
AC-power adapter
Required for Operation
You will also need the following Davis weather products to use your Envoy:
All Weather Envoys:
Any version of WeatherLink for Vantage Pro and Vantage Pro2 (Windows
version 5.2 or later (6510USB, 6510SER, 6540, 6550, 6560, #6510C),
Mac OS X version 5.01 or later (6520, 6520C))
Wireless Weather Envoy:
Wireless ISS or ISS Plus (6320, 6322, 6325, 6328) or;
Wireless Vantage Pro2 (Plus) Weather Station (6152, 6153, 6162, 6163)
Cabled Weather Envoy:
Cabled ISS or Cabled ISS Plus
Optional Accessories
The following optional accessories are designed for use with your Envoy.
They are available from your dealer or may be ordered directly from Davis
Telephone Modem Adapter (#6533) (For Serial Connections only) Allows transmission of data from the data logger using a modem.
Hardware Installation
Standard 4-Conductor 40' Extension Cable (#7876-040) (For Serial
connections only) - For more flexibility in the placement of your Weather
Envoy, add one 40' (12 m) extension cable to extend the distance between
your station and the computer. (48' (14.4 m) maximum)
Hardware Installation
The Weather Envoy can be installed and connected to a computer two different
ways: via a local connection to a computer (using either the USB or serial
connection type) and remote connection to a computer via a modem.
Requirements and installation for each type of connection differ, and are
explained separately below.
Local Connection Windows Computer Requirements
WeatherLink is compatible with computers using a USB port connection
running the following platforms: 98 SE, ME, 2000 or XP.
WeatherLink is compatible with computers using a serial port connection
running the following platforms: 95 (with Internet Explorer 4.0 or higher), 98,
98 SE, ME, NT 4.0, 2000 or XP.
Your Weather Envoy and WeatherLink also require the following for a local
Windows computer connection.
Windows-compatible display.
VGA minimum. SVGA or High (16-bit) Color or better recommended.
One free serial port or USB Port.
Local Connection Macintosh Computer Requirements
Your Weather Envoy requires the following for a local Macintosh computer
Macintosh computer running Mac OS X v10.01 or newer with at least 5
MB of free disk space.
One free USB Port.
Preparing the Envoy
Perform the following procedures to prepare your Envoy for operation.
Install the Data Logger
Install the Batteries and Optional AC power source
Mount your Envoy
Connect Envoy to WeatherLink software
Test using WeatherLink software
Setup the Envoy using WeatherLink software
Install the Data Logger
Installing the data logger that is supplied with the WeatherLink package is first
step in preparing the Weather Envoy to transmit data to the WeatherLink software.
Install the Data Logger
CAUTION: Plugging or unplugging the data logger while power is applied to the Envoy can
lock up or damage the logger. The WeatherLink data logger must be installed
before you install the batteries.
1. Remove the three screws from the back of the Envoy case
2. Separate the case halves to expose the data logger connector.
Install the Batteries
3. Carefully insert the data logger (Serial or USB) into the connector slot,
making sure to push data logger firmly in place.
USB Data Logger
Serial Data Logger
Data Logger Cable Channel
Data Logger Cable Channel
4. Rejoin the case halves, making sure the data logger cable passes through the
cable channel.
5. Fasten using the three screws you previously removed.
Install the Batteries
1. Find the battery cover on the back side of the Envoy case.
2. Remove the battery cover by pressing on the arrow embossed on the cover
and sliding the cover away from the case.
3. Insert the three AA-cell batteries, negative terminal (flat side) first.
4. The Envoy runs through a brief self-test procedure. The Envoy emits two
beeps if the test is successful.
5. Replace the battery cover on the case.
Mount Your Weather Envoy
Optional: Connecting AC Power
The operating battery power for a cabled Weather Envoy is approximately 10
days. For a wireless Weather Envoy, the battery power is approximately 5
months. The Weather Envoy is supplied with an option AC power adapter that
can be installed as an optional power source.
If installing the optional AC power supply, make sure the WeatherLink Data Logger is
already installed and that the backup batteries are installed
1. Locate the power adapter jack on the end of the Envoy case. It’s next to the
data logger output cable.
Data Logger
AC Power
From Integrated
Sensor Suite
(cabled models only)
2. Insert the power adapter plug into the power jack.
Optional: Connecting a Cabled Envoy to the Integrated Sensor Suite (ISS)
Refer to the figure shown above “Connecting AC Power”.
1. Insert the modular plug into the ISS jack on the Envoy case.
You won’t be able to test the connection between the Envoy and the ISS until you
have finished installing the WeatherLink software.
Mount Your Weather Envoy
You can place your Envoy on your desktop or you can install it on a wall near
your computer. Here are some guidelines for placing your Weather Envoy.
Mount Your Weather Envoy
Envoy Location
You should place the Envoy in a location where it easily accessible and can be
easily connected to a computer. For more accurate readings, follow these suggestions:
Avoid placing the Envoy in direct sunlight. This may cause erroneous
inside temperature and humidity readings and may damage the unit.
Avoid placing the Envoy near radiators or heating/air conditioning ducts.
If you are mounting the Envoy on a wall, choose an interior wall. Avoid
exterior walls that tend to heat up or cool down depending on the weather.
The range of the radio transmission that the Envoy can receive from the wireless ISS depends on several factors. Try to position the Envoy around the
transmitting weather station as close as possible for best results.
Typical maximum ranges include:
Line of sight: 1000 feet (300 m).
Under most conditions: 200 - 400 feet (60 - 120 m).
Other range and transmission considerations include:
Range may be reduced by walls, ceilings, trees, foliage, a metal roof or
other large metal structures or objects such as aluminum siding, metal
ducts, and metal appliances, such as refrigerators.
Frequency interferers also reduce transmission distance. Cordless phones
(900 Mhz) is a common example of frequency interference.
Transmission between wireless units may be obscured by something unidentifiable, or by some obstacle that can’t be worked around.
For best results, orient the ISS antenna and the Envoy antenna so that the orientation and angles of the antennas are parallel to each other.
If possible, align the pivot joints of both the ISS and the Envoy antennas so
that the are facing each other for maximum signal strength.
For better reception over greater distances or for weaker signals, consider using a Wireless Repeater (product #7626 or #7627) to strengthen the signal or increase the distance
between your ISS and the Envoy.
Wall Mounting the Envoy
Use this procedure for a wall installation.
Local Computer Installation
1. Use the provided wall mounting template as
an example of hole spacing and alignment
when installing your Envoy.
2. Use the template as a guideline for the hole
markings on the wall where you want to
mount the Envoy, and use a pencil to mark
the location for the two mounting screws.
The screws should be 3.25'' (82.5 mm) apart
and lined up vertically.
3. Drill the marked locations with a 3/32'' or 7/
64'' (2.2 to 2.7 mm) drill bit.
4. Drive the two #6 x 1'' (3.5 mm x 25 mm) pan
head self-threading screws into the wall.
5. Leave at least a 1/8'' (3 mm) space between
the wall and the heads of the screws.
Drill 3/32"
or 7/64"
(~2.2 to 2.7mm)
6. Slide the keyholes on the back of the
case over the two screw heads.
#6 x 1"
Local Computer Installation
The instructions below contain the base procedures for connecting and setting
up a local or remote connection between your Weather Envoy and a computer.
Additional setup not featured in this manual is required for all Weather Envoy,
Vantage Pro and Vantage Pro2 consoles. See the WeatherLink Getting Started
Guide for complete instructions on connecting the data logger to your computer. Also, see WeatherLink Online Help for additional setup instructions.
Local Computer Installation
USB Connection
Complete the local USB connection by using the instructions below:
1. Locate the Envoy receiving the WeatherLink USB connection.
2. Locate a free USB port on your computer and connect the USB connector
to the port.
3. Insert the USB - Mini B connector on the USB connector of the USB data
logger. The connection between the Envoy and the computer can be
extended up to 16’ (5 m) using a USB-to-USB connector cable.
Do not attempt to use more than a 16’ extension cable, or the data logger may have
difficulty communicating with the computer.
Serial Port Connection
These instructions explain how to make a typical local connection between
your Envoy and your computer via a serial port. Note that if you extend the
cable run beyond 48' (14.4 m), the software may have difficulty communicating with the station
Installing with a Local Computer
1. Locate a free serial port on the back of your computer and connect the DB9
to the port.
2. Insert the cable plug at the end of the short cable coming from the data logger into the receptacle on the end of the 8’ cable. Then insert the cable plug
on the end of the 8’ cable into the DB9 adapter.
The cable connecting the data logger to the computer is 8’ (2.4 m) long. If
you need to place the station Envoy more than 8’ from the computer, use a
40’ (12 m) standard 4-conductor extension cable (#7876-040). Do not
attempt to use more than 40’ of extension cable, or the data logger may
have difficulty communicating with the computer.
Remote Computer Installation
Optional 40' (12 m) 4-Conductor
Extension Cable and Coupler
Weather Envoy
Data Logger
8' (2.5 m) Cable
AC Power
The data logger does not require a constant connection with a computer to continue
logging and storing data. Although the data logger should remain connected to the
Envoy at all times, the data logger only needs to be connected to the computer when
data is being downloaded or when the computer is actively using data from the data
logger. The data logger and Envoy can be disconnected from the computer if the
Envoy is placed in a location where the data logger cable cannot reach. However,
WeatherLink’s bulletin, summary, or other real-time window displays are only accessible if the Envoy is attached to the computer.
Remote Computer Installation
The illustration below shows a typical remote computer installation using a
modem. This involves connecting the data logger to the Weather Envoy and to
a modem at the station Envoy site and connecting your computer’s modem to
a phone line, which will allow you to dial the Weather Envoy.
Mac Users - Refer to your WeatherLink for Mac OS X Getting Started Guide for additional installation instructions
Weather Envoy
with Data Logger
Windows Computer
External or
Internal Modem
25-pin Telephone Modem
Adapter (#6533)
8 feet (2.5 m)
Data Logger Cable
Remote Modem Connection Notes
Before installing the Envoy and modem at a remote location, test the data logger and
connection first using a direct connection like that shown in the section above.
Remote Modem Connection Hardware Requirements
The following additional hardware is required for a phone modem connection.
One internal or external modem connected to your computer. The modem
must be Hayes®–compatible and run at 1200, 2400, 4800, 9600, 14400 or
19200 baud.
One external modem to connect to the Weather Envoy data logger. The
modem must be Hayes®–compatible and run at 1200, 2400, 4800, 9600,
14000 or 19200 baud.
Telephone Modem Adapter
The Telephone Modem Adapter (#6533) provides the connection between
the Weather Envoy data logger and the modem.
Installing with a Remote Computer
1. Install and set up an internal or external modem (according to the
instructions supplied by the manufacturer) for use with your computer.
Make a note of the COM port used by the modem. You will need this information when entering serial port settings for the station.
2. At the Weather Envoy site, put the external modem in a location where it
can connect to both the data logger and the phone jack.
Both the modem and the Weather Envoy should be powered down at this time, if they
are not already turned off.
The cable connecting the data logger to the modem is 8' (2.4 m) long. If you
need to mount the station Envoy more than 8' from the modem, use a 40' (12
m) standard 4-conductor extension cable. Do not attempt to use more than
40' of extension cable, or the data logger may have difficulty communicating with the modem.
Plug the external modem into the phone jack.
Connect the Weather Envoy data logger to the modem.
Power up the modem.
Power up the Weather Envoy last.
Remote Modem Connection Notes
When accessing a remote modem connection, WeatherLink automatically
dials the station and Envoy whenever an action has been performed in the software that requires it to talk to the station.
While connected to a remote station, an On-Line icon displays in the toolbar.
This icon indicates that WeatherLink has established a connection with the
remote Envoy and weather station. Select the On-Line icon from the toolbar
or select Hang Up from the File menu to disconnect the phone connection.
Installing the Software
By default, WeatherLink hangs up the connection to the modem after one
minute without any communication with the station. Use the Communications Port dialog box in the Setup menu of WeatherLink to change this
default value. (See the WeatherLink help files for more information.)
WeatherLink will not hang up the phone line if the Bulletin or Summary windows are
Software Installation and Setup
Refer to the following procedure to install WeatherLink software on your computer. The instructions below contain the base procedures for running the
WeatherLink software and setting up a connection to your Weather Envoy. All
information about the software is included as an overview. Additional setup
not featured in this manual is required for all Weather Envoy, Vantage Pro and
Vantage Pro2 consoles. See WeatherLink Online Help for complete setup
If you are installing a Davis specialized data logger (6540, 6550, 6560) please see
the included addendum for complete installation instructions.
Installing the Software
Windows Computer Using USB Connection
Follow the steps below to install the WeatherLink software.
1. Place the WeatherLink software CD in your CD ROM drive.
The install program should start automatically. If the install program does
not start, select Run from the Start menu, type D:\SETUP (or the correct
letter for your CD ROM drive), and click OK to begin the installation.
2. Follow the on-screen prompts to complete the installation.
The USB drivers included with the Installation CD require extra steps to install. See
the WeatherLink Getting Started Guide for Vantage Pro and Vantage Pro2 for complete instructions on connecting the USB data logger to your computer and setting up
the WeatherLink Software to create the USB connection.
Windows Computer Using a Serial Port Connection
1. Place the Install Disk in your CD ROM drive.
Running the Software
The install program should start automatically. If the install program does
not start, choose Run from the Start menu, type D:\SETUP (or E:\SETUP,
substituting the correct drive letter for D or E), and choose OK to begin the
2. Follow the on-screen prompts to complete the installation.
Macintosh Computer
Place the Install Disk in your CD ROM drive.
Copy “install.sit” from the CD to your desktop and open it.
The installation software will automatically extract itself.
Run “install”.
Follow the on-screen prompts to complete the installation.
Running the Software
To run the software, double-click the WeatherLink icon. If no stations have
been assigned in the program directory, the software prompts you to add a station (see below for details). If there is more than one station in the program
directory when the application opens, the last station that was displayed is
automatically opened.
Adding a Station
1. Select New Station from the File menu. The New Station dialog displays.
2. Type the desired station name (up to 40 characters/spaces) into the Station
Name text box. The software uses the first eight characters of the station
name (not counting spaces or punctuation marks) as the name of the directory into which it saves this station’s database and configuration files. The
first eight characters of each station name must, therefore, be unique.
3. Click OK to save the new station or click Cancel to exit without saving.
The software saves the new station, creates a directory and a configuration
file for the station, and prompts you to enter the walk-through procedure.
About the Walkthrough
The software includes a station setup walkthrough that steps you through the
weather station configuration procedures. After adding a new station, the
Walkthrough dialog box automatically displays. By selecting Yes, the walkthrough process begins. By selecting No, the Walkthrough process is exited.
You can set up and configure your station by separately selecting all of the
necessary setup options from the Setup menu. A Walkthrough option is
included in the Setup menu that allows you to access the Walkthrough at any
By selecting the Walkthrough process, the software displays a series of dialog
boxes. At each step in the Walkthrough process, confirmation boxes are provided to perform or skip the next step in the Walkthrough. To continue, select
Running the Software
OK. To skip this step and move to the next step, select Skip. To cancel the
entire walkthrough process, select Cancel.
The Walkthrough, as well as all the options in the Setup menu, is the only interface for
configuring all the Weather Envoy setup options, such as Time and Date and Latitude
and Longitude settings. Please refer to the WeatherLink online help for more information about the Walkthrough.
Communication Port Settings
WeatherLink contains a dialog box for locating the communications port
(either USB or serial) that the data logger and Weather Envoy are connected
to. Use the Communications Port dialog box to select the communications
port that is used to communicate with the Envoy.
1. Select Communications Port from the Setup menu or use the Walkthrough
to display the dialog box. The Communications Port dialog box displays.
2. Click Auto Detect. The program searches for the port that the Envoy data
logger is connected to. When the correct connection is found, the following
dialog box displays:
3. Click OK. The Communications Port dialog box displays with the correct
port selected in the Com Port drop down box.
Running the Software
4. Select the desired baud Rate from the Baud Rate drop down box.
19200 is the default baud rate for the Weather Envoy data logger.
5. Click OK to select the port settings and exit the dialog.
Set Alarms
You may quickly set the alarm thresholds on the Weather Envoy using the
WeatherLink software. See the Alarms section in this manual for more information on the types of alarms available and how they work.
The only way to clear an alarm in the Weather Envoy is to modify the threshold in the
Alarm Setup screen to a value that would not cause an alarm, or to delete the value
1. Select Set Alarms from the Setup menu or press Ctrl-A.
The Set Station Alarms dialog box displays.
Enter the following information:
High/Low Alarm - For all standard high/low alarms, enter the desired alarm
threshold into the text box. To clear an alarm, clear the contents of the text box
or enter two (2) dashes: "--".
Barometer - Enter the 3-hour low (fall) and /or high (rise) pressure trend thresholds. To clear an alarm, clear the contents of the text box or enter two (2) dashes:
"--" (two dashes).
Running the Software
Time - Enter the time for the alarm in the text box. To clear the alarm, clear the
contents of the text box or enter two (2) dashes: "--".
2. When finished entering alarm information, choose Set.
The software sets the alarms on the station Envoy to match the settings in
this dialog box.
Auto Download
You may set up the software to automatically download data at specified times
each day (the software must be running and a constant connection to the data
logger in the Envoy must be made).
1. Select Auto Download from the Setup menu or press Ctrl-J.
The Auto Download dialog box appears. The stations which appear in the
Auto Download List will be downloaded automatically.
2. To add a station to the Auto Download List, double-click on the station
name or select the station from the Station Names list and click Add.
The station name moves to the Auto Download List. You may select more
than one station before clicking Add to add several stations at once. You
may quickly add all stations in the Station Names list by clicking Add All.
3. To remove a station from the Auto Download List, select the station and
click Remove.
The station name removes from the Auto Download List. You may select
more than one station before clicking Remove to remove several stations at
once. You may quickly remove all stations in the list by choosing Clear.
4. To set the time(s) at which the selected station should be downloaded,
choose Download At.
The Download At dialog box appears.
5. Enter the following information:
Download Times - Select the hour(s) at which the software should automatically download information from this station by clicking on the desired hour in
the list. You may select as many download hours as you want; the software will
download data from your station during each of the specified hours. To de-select
a previously selected hour, click on it again. To quickly select all hours, choose
Choose All. To quickly clear all selected hours, choose Clear.
Offset Time - To force the software to automatically download a specific number of minutes after the selected hour(s), enter the number of minutes here. For
example, in the illustration above the software would automatically download at
8:05 and 9:05 am.
6. After setting the download time(s), click OK.
The software saves the automatic download time settings.
The Weather Envoy features more than 30 alarms that can be programmed to
sound whenever a reading exceeds a set value. With the exception of barometric pressure and time, all alarms sound when a reading reaches the alarm
threshold. For example, if the high outside temperature alarm threshold is set
at 65 ºF, the alarm will sound when the temperature rises to 65.0 ºF.
Weather Data Measured & Calculated
Low alarms work the same way. For example, if the wind chill threshold is set
for 30 ºF, the alarm begins sounding when the temperature drops to 30.0 º and
will continue until the temperature again rises above 30.0º.
If you’re on battery power, the alarm will sound for two minutes only. If
you’re using the AC adapter, the alarm will continue as long as the condition
exists. The alarm will also sound again for each new alarm.
To silence a sounding alarm, edit the Alarm setup screen to either delete the
alarm threshold or to modify the threshold so that the current conditions don’t
cause an alarm.
Three special alarms
ET (Evapotranspiration)
ET is updated only once an hour, on the hour. If during a given hour the ET
Value exceeds the alarm threshold, the ET alarm sounds at the end of that hour.
This is true for daily, monthly, and yearly ET alarms. You must have the
optional Solar Radiation Sensor to use this alarm.
Barometric Pressure
The Weather Envoy allows you to set two barometric pressure alarms: a “rise”
alarm and a “fall” alarm. You may select any rate of change per hour between
0.01 to 0.25 in Hg (0.1 to 6.4 mm Hg, 0.1 to 8.5 hPa/mb); the alarm will sound
if the rate of change (in the selected direction) exceeds the threshold you set.
The time alarm is a standard “alarm clock”. It sounds at the set tim. Make sure
you choose AM or PM, if you’re in 12-hour mode. It sounds for one minute.
Weather Data Measured & Calculated
This section outlines each of the weather conditions measured and/or calculated by the Weather Envoy, by the Vantage Pro Integrated Sensor Suite (ISS),
and by optional Vantage Pro sensors. Each section includes a brief discussion
of the weather condition and a listing of the various ways in which the unit displays or stores that condition. Be aware that some of the weather conditions
require an optional sensor in order to measure or calculate a value.
The anemometer measures wind speed and wind direction.
The Weather Envoy uses the ISS temperature sensor to measure the outside air
temperature. A second temperature sensor in the Weather Envoy measures the
inside air temperature. Additional temperature sensors (available only with
wireless Vantage Pro and Weather Envoy systems) can be used to measure
temperature in other locations. You may use these extra sensors to measure
any other temperatures that are within the sensor’s range, including liquids
such as water.
Weather Data Measured & Calculated
Apparent Temperatures
The Weather Envoy calculates three apparent temperature readings: wind
chill, heat index, and the temperature/humidity/wind index (THW Index).
Wind chill
Wind chill takes into account how the speed of the wind affects our perception
of the air temperature. Our bodies warm the surrounding air molecules by
transferring heat from the skin. If there’s no air movement, this insulating
layer of warm air molecules stays next to the body and offers some protection
from cooler air molecules. However, wind sweeps that comfy warm air surrounding the body away. The faster the wind blows, the faster heat is carried
away and the colder you feel.
Wind chill is not stored in archive memory. Wind chill is calculated whenever
it is displayed. Editing temperature or wind speed values changes the wind
chill value.
WeatherLink versions 5.1 and later use the Osczevski (1995) equation to calculate
wind chill. This is the adopted method used by the US National Weather Service.
Heat Index
The Heat Index uses the temperature and the relative humidity to determine
how hot the air actually “feels.” When humidity is low, the apparent temperature will be lower than the air temperature, since perspiration evaporates rapidly to cool the body. However, when humidity is high (i.e., the air is saturated
with water vapor) the apparent temperature “feels” higher than the actual air
temperature, because perspiration evaporates more slowly.
THW (Temperature - Humidity - Wind)
The THW Index uses humidity and temperature to calculate an apparent temperature, but includes the cooling and heating effects of wind on our perception of temperature.
THSW (Temperature - Humidity - Solar - Wind)
The THSW Index uses humidity and temperature to calculate an apparent temperature, including the cooling and heating effects of both and solar radiation
on our perception of the temperature.The THSW Index requires a solar radiation sensor.
Humidity itself simply refers to the amount of water vapor in the air. However,
the amount of water vapor that the air can contain varies with air temperature
and pressure. Relative humidity takes into account these factors and offers a
humidity reading which reflects the amount of water vapor in the air as a percentage of the amount the air is capable of holding. Relative humidity, therefore, is not actually a measure of the amount of water vapor in the air, but a
ratio of the air’s water vapor content to its capacity. When we use the term
humidity in the manual and on the screen, we mean relative humidity.
Weather Data Measured & Calculated
It is important to realize that relative humidity changes with temperature, pressure, and water vapor content. A parcel of air with a capacity for 10 g of water
vapor which contains 4 g of water vapor, the relative humidity would be 40%.
Adding 2 g more water vapor (for a total of 6 g) would change the humidity to
60%. If that same parcel of air is then warmed so that it has a capacity for 20 g
of water vapor, the relative humidity drops to 30% even though water vapor
content does not change.
Relative humidity is an important factor in determining the amount of evaporation from plants and wet surfaces since warm air with low humidity has a
large capacity for extra water vapor.
Dew-point is the temperature to which air must be cooled for saturation 100%
relative humidity) to occur, providing there is no change in water content. The
dew-point is an important measurement used to predict the formation of dew,
frost, and fog. If dew-point and temperature are close together in the late afternoon when the air begins to turn colder, fog is likely during the night. Dewpoint is also a good indicator of the air’s actual water vapor content, unlike relative humidity, which takes the air’s temperature into account. High dew-point
indicates high vapor content; low dew-point indicates low vapor content. In
addition a high dew-point indicates a better chance of rain and severe thunderstorms. You can even use dew-point to predict the minimum overnight temperature. Provided no new fronts are expected overnight and the afternoon
Relative Humidity ≥ 50%, the afternoon’s dew-point gives you an idea of what
minimum temperature to expect overnight, since the air is not likely to get
colder than the dew-point anytime during the night.
Vantage Pro2 incorporates a tipping-bucket rain collector in the ISS that measures 0.01'' for each tip of the bucket. A metric adapter can be installed to measure 0.2 mm for each tip of the bucket.Your station logs rain data in the same
units it is measured in and converts the logged totals into the selected display
units (inches or millimeters) at the time it is displayed. Converting at display
time reduces possible compounded rounding errors over time.
Four separate variables track rain totals: “rain storm”, “daily rain”, “monthly
rain”, and “yearly rain”. Rain rate calculations are based on the interval of
time between each bucket tip, which is each 0.01'' rainfall increment or .2 mm.
Barometric Pressure
The weight of the air that makes up our atmosphere exerts a pressure on the
surface of the earth. This pressure is known as atmospheric pressure. Generally, the more air above an area, the higher the atmospheric pressure, this, in
turn, means that atmospheric pressure changes with altitude. For example,
atmospheric pressure is greater at sea-level than on a mountaintop. To compensate for this difference and facilitate comparison between locations with
Weather Data Measured & Calculated
different altitudes, atmospheric pressure is generally adjusted to the equivalent
sea-level pressure. This adjusted pressure is known as barometric pressure. In
reality, the Weather Envoy measures atmospheric pressure. When you enter
your location’s altitude in Setup Mode, the Weather Envoy stores the necessary offset value to consistently translate atmospheric pressure into barometric
Barometric pressure also changes with local weather conditions, making barometric pressure an extremely important and useful weather forecasting tool.
High pressure zones are generally associated with fair weather while low pressure zones are generally associated with poor weather. For forecasting purposes, however, the absolute barometric pressure value is generally less
important than the change in barometric pressure. In general, rising pressure
indicates improving weather conditions while falling pressure indicates deteriorating weather conditions.
Solar Radiation
Requires optional solar radiation sensor (#6450, included on Vantage Pro Plus
weather stations).
What we call “current solar radiation” is technically known as Global Solar
Radiation, a measure of the intensity of the sun’s radiation reaching a horizontal surface. This irradiance includes both the direct component from the sun
and the reflected component from the rest of the sky. The solar radiation reading gives a measure of the amount of solar radiation hitting the solar radiation
sensor at any given time, expressed in Watts /sq. m (W/m2).
The solar radiation sensor measures energy received in the spectral band between
400 and 1100 nm.
UV (Ultra Violet) Radiation
Requires optional UV sensor (#6490), included on Vantage Pro Plus weather stations.
Energy from the sun reaches the earth as visible, infrared, and ultraviolet (UV)
rays. Exposure to UV rays can cause numerous health problems, such as sunburn, skin cancer, skin aging, and cataracts, and can suppress the immune system. The Weather Envoy can help analyze the changing levels of UV radiation
and can advise of situations where exposure is particularly unacceptable.
CAUTION: Be aware, however, that the UV sensor readings do not take into account UV
reflected off snow, sand, or water, which can significantly increase the amount of
UV to which you are exposed. Nor do the readings take into account the dangers of
prolonged exposure to UV radiation. The readings do not suggest that any amount
of exposure is safe or healthful. Do not use the UV readings to determine the
amount of UV radiation to which you expose yourself. Scientific evidence suggests
that UV exposure should be avoided and that even low UV doses can be harmful.
Weather Data Measured & Calculated
WeatherLink displays UV readings in two scales: UV, which is the amount of
UV radiation using the UV Index scale, and UV Dose, which displays an accumulated UV in MEDs.
MED stands for Minimum Erythemal Dose, defined as the amount of sunlight
exposure necessary to induce a barely perceptible redness of the skin within 24
hours after sun exposure. In other words, exposure to 1 MED will result in a
reddening of the skin. Because different skin types burn at different rates, 1
MED for persons with very dark skin is different from 1 MED for persons
with very light skin.
Both the U.S. Environmental Protection Agency (EPA) and Environment Canada have developed skin type categories correlating characteristics of skin
with rates of sunburn. Tables 3a and 3b below list these skin types.
Table A1: EPA Skin Phototypes
Skin Phototype
Skin color
Tanning & Sunburn history
1 - Never tans,
always burns
Pale or milky white;
Develops red sunburn; painful swelling,
skin peels
2 - Sometimes
tans, usually burns
Very light brown;
sometimes freckles
Usually burns, pinkish or red coloring
can gradually develop light brown tan
3 - Usually tans,
sometimes burns
Light tan; brown, or
distinctly pigmented
Rarely burns; shows moderately rapid
tanning response
4 - Always tans;
rarely burns
Brown, dark brown, or
Rarely burns; shows very rapid tanning
T. B. Fitpatrick of the Harvard Medical School developed a categorization of
skin types 1 through 6 which were adopted by Environment Canada. These
skin types are detailed in Table 3b below.
Table A2: Environment Canada Skin Types and Reaction to the Sun
Skin Color
History of Tanning & Sunburning
Always burns easily, never tans
Always burns easily, tans minimally
Light Brown
Burns moderately, tans gradually
Weather Data Measured & Calculated
Table A2: Environment Canada Skin Types and Reaction to the Sun
Skin Color
History of Tanning & Sunburning
Burns minimally, tans well
Dark Brown
Burns rarely, tans profusely
Never burns, deep pigmentation
More about the Fitzpatrick Skin Types is available in: Fitzpatrick TB. Editorial: the
validity and practicality of sun-reactive skin types I through VI. Arch Dermatol 1988;
UV Dose and Sunburn - Use this plot to estimate the MED dose leading to
sunburn. A person with Type II (Environment Canada) skin type might choose
0.75 MED as the maximum for the day; in contrast, a person with Type V
(Environment Canada) Skin Type might consider 2.5 MEDs a reasonable dose
for the day. NOTE: the Weather Envoy assumes a Fitzpatrick (Environment
Canada) Skin Type of II.
Skin Phototype (EPA)
All Burn
Some Burn
Skin Type (Environment Canada)
UV Dose that Causes Sunburn
UV Dose (MEDs)
120 mJ/cm
Weather Data Measured & Calculated
Weather Envoy can also display UV Index, an intensity measurement first
defined by Environment Canada and since been adopted by the World Meteorological Organization. UV Index assigns a number between 0 and 16 to the
current UV intensity. The US EPA categorizes the Index values as shown
below. The lower the number, the lower the danger of sunburn. The Index
value published by the U.S. National Weather Service is a forecast of the next
day’s noontime UV intensity. The Index value displayed by the Weather
Envoy is the result of a real-time measurement.
Table A3: UV Index and Exposure Category
Index Values
Exposure Category
Very High
EvapoTranspiration (ET)
Requires optional solar radiation sensor (#6450, included on Vantage Pro or Vantage
Pro2 Plus weather stations).
EvapoTranspiration (ET) is a measurement of the amount of water vapor
returned to the air in a given area. It combines the amount of water vapor
returned through evaporation (from wet vegetation surfaces and the stoma of
leaves) with the amount of water vapor returned through transpiration (exhaling of moisture through plant skin) to arrive at a total. Effectively, ET is the
opposite of rainfall, and it is expressed in the same units of measure (Inches,
The Weather Envoy uses air temperature, relative humidity, average wind
speed, and solar radiation data to estimate ET. (ET is calculated once an hour
on the hour.)
Please note that calculating ET requires the optional solar radiation sensor.
Leaf Wetness
Leaf Wetness is only available with the wireless Weather Envoy using the optional
Leaf and Soil Moisture/Temperature station (#6345) with a Leaf Wetness sensor
Leaf wetness provides an indication of whether the surface of foliage in the
area of the sensor is wet or dry by indicating how wet the surface of the sensor
is. The leaf wetness reading ranges from 0 (dry) to 15.
Troubleshooting Guide
Soil Moisture
Soil Moisture is only available with the wireless Weather Envoy using the optional
Leaf and Soil Moisture/Temperature station (#6345) with a Soil Moisture sensor
Soil Moisture, as the name suggests, is a measure of the moisture content of
the soil. Soil moisture is measured on a scale of 0 to 200 centibars, and can
help choose times to water crops. The soil moisture sensor measures the vacuum created in the soil by the lack of moisture. A high soil moisture reading
indicates dryer soil; a lower soil moisture reading means wetter soil.
The Weather Envoy has a clock and a calendar for tracking time and date. The
calendar automatically adjusts during leap years and daylight savings, providing you have entered the correct year, latitude and longitude, and daylight savings settings in the Setup Mode.
Troubleshooting Guide
The following section answers some of the most commonly asked questions
about WeatherLink® and the Weather Envoy. Please consult this guide and the
WeatherLink software Help before contacting Davis. Please see Contacting
Davis Technical Support on page 28 for more information.
Communications Problems
? Why can't the WeatherLink software communicate with the data logger and
If you are having trouble establishing communication between WeatherLink and the Weather Envoy, start by checking the weather station's own
diagnostics. Remove all power to the Weather Envoy and then restart it by
restoring power with the data logger still attached.
The data logger uses non-volatile memory, so you won’t lose any data you’ve already
Generally, if the loopback test identifies a serial port, your PC will be okay.
You should hear two beeps, each of which occurs when the weather station
passes one of its diagnostic tests. Each beep follows the previous after about a
second. The first beep tells you the processor is running. The second beep verifies the installation of the data logger. If you do not hear two beeps, contact
Davis Instruments at 510-732-7814.
If you hear both beeps, see Finding the Correct Serial Port on page 25 for
instructions on checking your standard serial ports. If this identifies a serial port
other than the one you selected in station setup, try connecting to the data logger
Remove any extension cables that are in the system.
Finding the Correct Serial Port
Make sure you are using the blue serial port adapter supplied with WeatherLink
for Vantage Pro. The older, black Davis serial adapters will not work.
If you still cannot connect or if the loopback test does not identify any
serial ports, eliminate the following possibilities. If you have questions
on how to proceed, contact your PC vendor or PC technical support.
You have a hardware device conflict.
Check the device manager tab in the Windows® system properties
dialog box to ensure that Windows recognizes your COM port. Consult
your pc’s documentation to see how to access the system properties
dialog box.
Your serial port uses a non-standard device name.
WeatherLink recognizes serial ports named COM1 through COM10
only. To use a modem, you must specify the underlying COM port on
your PC. To find out which port the modem’s connected to, you can
look in Windows’ System Properties > Device Manager > “modem
name” Properties > Modem > Port, where “modem name” is the name
of the modem you have installed.
Your serial port is defective.
The loopback connector or the WeatherLink adapter plug is bad.
Finding the Correct Serial Port
The software includes a procedure for locating the serial port to which your
station is connected or determining whether that serial port is working. Using
the Loopback command (as opposed to Test) will help you find the correct
port and determine whether the serial port or the data logger is causing a communication problem. The loopback function will also detect and report the
presence of any modems.
To use this procedure, you will need the loopback connector (the
short cable with a phone jack on one end and a red plastic tip on
the other) supplied with Weatherlink.
1. If necessary, disconnect the cable between your station and the
adapter connected to the COM port.
2. Insert the loopback connector into the adapter.
3. Select Communications Port from the Setup menu.
Finding the Correct Serial Port
The Communications Port dialog box displays.
4. Click Loopback.
The software searches all standard serial ports and inform you of the COM
port at which the loopback connector is located.
The software automatically selects the correct COM port for you in the
Communications Port dialog box. If it cannot find the loopback connector
at any COM port, your serial port may not be working. Consult your computer documentation for help.
Modem Initialization String
The software automatically enters the following modem initialization string in
the serial port settings dialog box, which should work with most modems:
AT &F S7=60 E Q V X4.
The individual components of the string have the following meaning.
AT - This string precedes all Hayes commands.
&F - Resets modem to factory defaults
S7=60 - Tells modem to wait a maximum of 60 seconds for remote modem
to answer and issue a data carrier.
• E - Turns echo off.
• Q - Tells the modem to return result codes.
Program Problems
V - Tells the modem to return short form result codes.
X4 - Enables result codes 0 to 7 and 10.
The software can troubleshoot some modem problems by presenting error
messages. For the software to provide error messages, any modem initialization string entered must contain the E, Q, and V strings.
If another communications program is used after using the modem with the WeatherLink Software, re-initialize the modem using the modem string expected by the other
Program Problems
? The barometer graph on the Bulletin does not “fill in” completely.
When you first load the bulletin, the barometer graph will only fill in completely when you have data in your database for the last six hours. Make
sure of the following:
There is data in your database for the span of the barometer graph.
The time and date of the stored barometer data is correct in your database.
The time and date on the PC is correct.
The time and date on the weather station are correct.
? No wind direction reading (or dashes instead of a reading) appears in my database.
Be aware that if there is no wind speed when the direction is being sampled,
wind direction is not recorded. During intervals with very little wind speed,
no direction may be recorded. Since high wind speed is sampled more
often, it is possible to have a high wind speed but no wind speed or direction.
? WeatherLink says “No new data to download” but I know there’s data there.
What can I do?
Weather Envoy is smart enough to send only data it hasn’t already sent to
the computer. So, when you initiate a new download, the program will
retrieve the first record after the last record shown in the WeatherLink’s
Browse Window. Older data is stored in the logger as a backup. To see how
many of these backup records are stored in the logger, create a new station
and download the data into this new database. Because there are no records
stored in the station you just created, WeatherLink will download everything it has stored.
Next, try clearing the archive memory using the clear dialog box. You will
lose any data not already downloaded in your archive memory, but all of
your calibration numbers and alarm settings will remain intact. If this
doesn’t work, reboot your weather station by removing all power including
batteries, then restoring power.
Contacting Davis Technical Support
? After successfully downloading, recent or new data does not appear to be in my
database. Where is it?
Check to see if the time and date on your station are incorrect. (This can
happen if you have a power outage and your battery is dead.) If so, the data
was written into the wrong month, day, and/or time. Reset the time and date.
It is also possible, if you have multiple stations, that you downloaded data
into the wrong station’s database. Make sure you’ve opened the correct station before downloading.
? When viewing data, dashes appear in place of a value for functions other than
wind direction. Why?
If no data was recorded by a sensor (for example, the sensor was disconnected or radio interference blocked reception) or if bad data was recorded
for a sensor (for example, the sensor was malfunctioning), the software
dashes out the entry rather than showing invalid data. You can use the
record editor to correct these entries.
Contacting Davis Technical Support
If you have questions about the software, or encounter problems installing or
operating the WeatherLink software, please contact Davis Technical Support.
(510) 732-7814 – Monday – Friday, 7:00 a.m. – 5:30 p.m. Pacific Time.
(510) 670-0589 – Technical Support Fax. – E-mail to Technical Support. – General e-mail. – Copies of User Manuals are available on the “Support” page. Watch for FAQs and other updates. Subscribe to the e-newsletter.
Operating Temperature. . . . . . . . . . . .+14° to +140°F (-10° to +60°C)
Non-operating Temperature . . . . . . . .-13° to +158°F (-25° to +70°C)
Current Draw, Wireless . . . . . . . . . . .0.90 mA average, 20 mA peak, (plus .125 mA
for each optional wireless transmitter in use)
at 4 to 6 VDC
Current Draw, Cabled . . . . . . . . . . . .10 mA average, 15 mA peak at 4 to 6 VDC
AC Power Adapter . . . . . . . . . . . . . . .5 VDC, 200 mA, regulated
Batteries . . . . . . . . . . . . . . . . . . . . . .3 AA-cells
Battery Life, Wireless . . . . . . . . . . . . .up to 6 months
Battery Life, Cabled . . . . . . . . . . . . . .up to 1 month
Connectors . . . . . . . . . . . . . . . . . . . . .Modular RJ-11
Cable Type . . . . . . . . . . . . . . . . . . . . .4-conductor, 26 AWG
Housing Material. . . . . . . . . . . . . . . . .UV-resistant PVC plastic
Communications (Wireless Models Only)
Wireless (includes antenna) . . . .6.5" x 3.75" x 1.5" (165 mm x 95 mm x 38 mm)
Cabled . . . . . . . . . . . . . . . . . . . .6.5" x 3.75" x 1.5" (165 mm x 95 mm x 38 mm)
Weight (with batteries) . . . . . . . . . . . .0.58 lbs. (0.26 kg)
Communications (Wireless Models Only)
Transmit/Receive Frequency . . . . . .US Models: 902-928 MHz FHSS, Overseas
Models: 868.0 - 868.6 MHz FHSS.
ID Codes Available . . . . . . . . . . . . . .8
Output Power . . . . . . . . . . . . . . . . . .902-928 MHz FHSS: FCC-certified low power,
less than 8 mW, no license required
868.0 - 868.6 MHz FHSS. CE-certified, less
than 8 mW, no license required
Line of Sight . . . . . . . . . . . . . . . .up to 1000 feet (300 m)
Through Walls . . . . . . . . . . . . . . .200 to 400 feet (75 to 150 m)
Sensor Inputs
RF Filtering . . . . . . . . . . . . . . . . . . . .RC low-pass filter on each signal line
Sensor Outputs
Inside Temperature
Resolution and Units . . . . . . . . . .Current Data: 0.1°F or 1°F or 0.1°C or 1°C
Historical Data and Alarms: 1°F or 1°C (userselectable)
Range . . . . . . . . . . . . . . . . . . . . .+32° to +140°F (0° to +60°C)
Sensor Accuracy . . . . . . . . . . . . .±1°F (±0.5°C) up to 110°F (43°C), ±2°F
(±1°C) over 110°F (43°C)
Update Interval . . . . . . . . . . . . . .1 minute
Current Data . . . . . . . . . . . . . . . .Instant Reading (user adjustable); Daily and
Monthly High and Low
Historical Data. . . . . . . . . . . . . . .Hourly Readings; Daily and Monthly Highs
and Lows
Alarms . . . . . . . . . . . . . . . . . . . .High and Low Thresholds from Instant
Barometric Pressure (sensor located in console)
Resolution and Units . . . . . . . . . .0.01" Hg, 0.1 mm Hg, 0.1 hPa/mb (userselectable)
Corrected Range . . . . . . . . . . . . .26.00" to 32.00" Hg, 660.0 to 810.0 mm Hg,
880.0 to 1080.0 hPa/mb
Uncorrected Range . . . . . . . . . . .18.00" to 33.50" Hg, 457.0 to 850.0 mm Hg,
592.0 to 1130.0 hPa/mb
Elevation Range . . . . . . . . . . . . .-999’ to +12,500’ (-305 m to 3810 m)
Uncorrected Reading Accuracy . .±0.03" Hg (±0.8 mm Hg, ±1.0 hPa/mb) (at
room temperature)
Sea-Level Reduction Equation UsedUnited States Method employed prior to
use of current "R Factor" method
Equation Source . . . . . . . . . . . . .Smithsonian Meteorological Tables
Equation Accuracy . . . . . . . . . . .±0.01" Hg (±0.3 mm Hg, ±0.3 hPa/mb)
Elevation Accuracy Required. . . .±10’ (3m) to meet equation accuracy
Overall Accuracy . . . . . . . . . . . . .±0.04" Hg (±1.0 mm Hg, ±1.4 hPa/mb)
Communications (Wireless Models Only)
Trend (change in 3 hours) . . . . . .Change ±0.6" (2 hPa/mb, 1.5 mm Hg) =
Change ±0.2" (.7hPa/mb, .5 mm Hg)= Slowly
Trend Indication . . . . . . . . . . . . .5 position arrow: Rising (rapidly or slowly),
Steady, or Falling (rapidly or slowly)
Update Interval . . . . . . . . . . . . . .15 minutes or when console BAR key is
pressed twice
Current Data . . . . . . . . . . . . . . . .Instant, 15-min., and Hourly Reading; Daily,
Monthly, High and Low
Historical Data. . . . . . . . . . . . . . .15-min. and Hourly Reading; Daily, Monthly
Highs and Lows
Alarms . . . . . . . . . . . . . . . . . . . .High Threshold from Current Trend for Storm
Clearing (Rising Trend
Low Threshold from Current Trend for Storm
Warning (Falling Trend)
Range for Rising and Falling Trend Alarms0.01 to 0.25" Hg (0.1 to 6.4 mm Hg,
0.1 to 8.5 hPa/mb )
Inside Relative Humidity (sensor located in console)
Range . . . . . . . . . . . . . . . . . . . . .10 to 90% RH
Accuracy . . . . . . . . . . . . . . . . . . .±5%
Update Interval . . . . . . . . . . . . . .1 minute
Current Data . . . . . . . . . . . . . . . .Instant (user adjustable) and Hourly Reading;
Daily, Monthly High and Low
Historical Data. . . . . . . . . . . . . . .Hourly Readings; Daily, Monthly Highs and
Alarms . . . . . . . . . . . . . . . . . . . . High and Low Threshold from Instant Reading
Resolution . . . . . . . . . . . . . . . . . .1 minute
Units . . . . . . . . . . . . . . . . . . . . . .Time: 12 or 24 hour format (user-selectable)
Date: US or International format (userselectable)
Accuracy . . . . . . . . . . . . . . . . . . .±8 seconds/month
Adjustments . . . . . . . . . . . . . . . .Time: Automatic Daylight Savings Time (for
users in North America, Europe and Australia
that observe it in AUTO mode, MANUAL
setting available for all other areas) Date:
Automatic Leap Year
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