                         Appendix A

                 Barometer And Power Status Bits


     The GroWeather, Energy, and Health systems all include bit-
mapped flags that indicate the status of the Bar Trend Arrows and
the Power Level Status located both on the station, and in the
sensor image. The address on all three links is 0x10E (The start
of the sensor image) and is 2 nibbles in length. This value is
updated at least every 16 seconds and at the time the sensor
image is sampled. Please see the appropriate memory map if you
would like to access the copy on the station since it is at
different locations on different stations.

     The Monitor, and Perception stations have the Barometer
trend information available on the station only.

     The Bit numbers given below refer to the one byte value
found in the sensor image.


         Bit #  Bit Name        Bit #  Bit Name
          0     Bar Steady       4     ---------
          1     Bar Rising       5     ---------
          2     Bar Falling      6     Battery Low
          3     ----------       7     Primary Power
                                       Low

     If the Bar Steady bit is set, ignore the value of the Bar
Rising and Bar Falling bits.

     If the Battery Low bit is set, then the voltage on the
backup battery input is less than 7.5 volts, If the Primary Power
Low bit is set, then the voltage on the primary power input is
less than 9.3 volts. Note that this voltage is less than the
range used by the Primary Power Voltage Codes, and that the
station will run with input voltages as low as 6 volts.


                         Appendix B

            Control Module communication status codes

     The current Control Module communication status is based on
statistics measured over the preceding minute. Two values are
accumulated: the number of unsuccessful loads, and the number of
unsuccessful loads that were preceded by 2 unsuccessful loads.
When the second condition is true, the CM-OK light times out.
Each minute, a status code is determined from the two counts by
looking up in the following table. The resulting code is the
higher of the two codes calculated from each value separately.

     The count numbers are based upon 3 seconds between load
attempts which gives us approximately 20 attempted loads per
minute.


                                        # Load    # Consecutive
   Code  Condition                      errors       errors
    0    Excellent - No errors             0            0
    1    OK - intermittent errors        1-4            0
    2    Bad - errors more common        5-9          1-4
    3    Very Bad - errors very common  10-14         5-9
    4    Not Connected - 3/4+ errors      15+          10+


                          Appendix C

                        Model Numbers


     The Davis line of weather stations contain a one nibble
model number to help determine what kind of station you are
connected to. This code is found at address 0x04D. The
GroWeather, Energy and Health links will mirror the station's
model number at the same address, while the Monitor, Wizard, and
Perception links have the value 0xF

            Model #  Model Name  Model #  Model Name
              0      Wizard III    8      ----
              1      Wizard II     9      ----
              2      Monitor       A      ----
              3      Perception    B      ----
              4      GroWeather    C      ----
              5      Energy        D      ----
              6      Health        E      ----
              7      ----          F      Old Link



                           Appendix D

                       Power Voltage Codes


     In the GroWeather and Energy systems, the primary power
voltage is made available in the station processor memory and in
the archive image (and archive records) to evaluate the
performance of solar powered stations. The current value is
located at address 0x1DD on both stations in a one nibble field.
The link will contain the value at the most recent archive
interval at location 0x1DE in a 2 nibble field which may be
easier to access.
     The voltage range covered is 10.25-13.75 volts in 1/4 volt
increments. In the following chart, Range indicates the voltage
range assigned the given code Value , Voltage gives the voltage
value that Davis' software reports for the given code Value.

   Value Range        Voltage    Value Range        Voltage
   0     0-10.24      <10.25 V   8     12.00-12.24   12.00 V
   1     10.25-10.49   10.25 V   9     12.25-12.49   12.25 V
   2     10.50-10.74   10.50 V   A     12.50-12.74   12.50 V
   3     10.75-10.99   10.75 V   B     12.75-12.99   12.75 V
   4     11.00-11.24   11.00 V   C     13.00-13.24   13.00 V
   5     11.25-11.49   11.25 V   D     13.25-13.49   13.25 V
   6     11.50-11.74   11.50 V   E     13.50-13.74   13.50 V
   7     11.75-11.99   11.75 V   F     13.75--      >13.75 V



                         Appendix E

                      THSWI Latitude Codes

     The Health station uses the approximate latitude to estimate
the height of the sun near noon for each month. This values
influences how the solar rad readings affect the Temperature-
Humidity-Sun-Wind Index. The number in the Latitude Code column
is the value stored on the station. The Latitude Display column
indicates what the LCD displays when setting the Latitude Cal
number. The Latitude Range is the range of latitudes that should
use this latitude code.

                Latitude Latitude    Latitude
                  Code   Display      Range
                    0     -55      90 S - 50S
                    1     -45      50 S - 42 S
                    2     -40      42 S - 37 S
                    3     -35      37 S - 32 S
                    4     -30      32 S - 27 S
                    5     -25      27 S - 22 S
                    6       0      22 S - 22 N
                    7     +25      22 N - 27 N
                    8      30      27 N - 32 N
                    9      35      32 N - 37 N
                   10      40      37 N - 42 N
                   11      45      42 N - 47 N
                   12      50      47 N - 52 N
                   13      55      52 N - 57 N
                   14      60      57 N - 65 N
                   15      70      65 N - 90 N



                         Appendix F

                   Wind Direction Sector Codes

     When the WeatherLink reports the prevailing wind direction
in the archive, and when the direction of the hi wind speed is
reported on the GroWeather, Energy, and Health stations, it is
reported as a number between 0 and 15. These correspond to the 16
compass rose directions. The compass points are numbered
clockwise starting with North.

       Dir Code   Direction     Dir Code   Direction
          0           N            8       S
          1         NNE            9     SSW
          2          NE            10     SW
          3         ENE            11    WSW
          4           E            12      W
          5         ESE            13    WNW
          6          SE            14     NW
          7         SSE            15    NNW


     If there is some reason that the wind direction data should
be ignored (i.e. the anemometer is broken, disconnected, or there
wasn't any wind during the archive interval), then the archived
data will have the value 255 instead of a number from the above
table. To check the validity of the hi wind speed direction on
the GroWeather, Energy and Health stations, you will need to
check the "BadHiDir" bit in the "DirFlags" register. If this bit
is 1, then ignore the value of the "HiDir" register.


                         Appendix G1

            Alarm Bit Definitions for the GroWeather

     These tables list the alarm bits for the GroWeather. There
are 2 different sets of bit assignments. One is the set available
on the Link in the sensor image. The second set is the bits sent
to the control module:

                      Alarm bit definitions
   Bit    Alarm          Bit    Alarm           Bit     Alarm
   Number Function       Number Function        Number  Function
   0      Time           8      Soil Temp - Low 16      Hum - Low
   1      Daily ET       9      Soil Temp - Hi  17      Hum - Hi
   2      Dew Point      10     User 1          18      Not Used
   3      Total ET       11     Temp-Hum Index  19      Reserved

   4      Barometer      12     Wind Chill      20      CM Status
   5   Total Degree Days 13     Wind Speed      21      CM Status
   6      Air Temp - Low 14     User 2          22      CM Status
   7      Air Temp - Hi  15     Daily Rain      23      CM Status


               Alarm Output module bit definitions

           Bit    Alarm Output     Bit    Alarm Output
           Number Module Function  Number Module Function
           1      Daily Rain       9      Air Temp - Hi
           2      User 2           10     Air Temp - Low
           3      Wind Speed       11     Hum - Hi
           4      Wind Chill       12     Hum - Low

           5      Temp-Hum Index   13     Reserved
           6      User 1           14     Dew Point
           7      Soil Temp - Hi   15     Daily ET
           8      Soil Temp - Low  16     Time

                             Notes:
     User 1 and User 2 are two user controllable bits that can be
       set through the PC.
     CM Status is a one nibble code that describes the status of
       the communication link between the control module and the
       weather station.
     Reserved is a bit reserved by Davis Instruments for future
       use. (for example to control a radio transmitter or solar
       powered battery charger)

    The Alarm Output Module assignments given above match the pin
numbers on the AOM board. Besides numbering from 1 instead of 0,
the order has been reversed, since the first bit sent ends up in
the high order position of the AOM's shift register.


                         Appendix G2

                       ET Error Flag bits

     The upper byte of the Archive Image ET field contains 8
Error flags that show the quality of the ET Calculation. There
are 2 types of bits: the first 5 bits correspond to the various
sensors, the remaining 3 bits indicate whether the station was
able to compute ET with the available sensors. The rad and wind
terms are components of the ET calculation that reflect the part
of the ET generated by solar radiation and wind respectively. If
neither of these terms can be calculated, then the "Bad ET" bit
is set.
     The purpose of these bits is to record what caused an ET
calculation to fail. Also, if a partial calculation is possible,
it is done and flagged with the appropriate bits.
     The Bits are as follows:

Bit #  Bit Name   Type of Error  Bit # Bit Name      Type of Error
 0     Bad Wind   Sensor          4    Bad Bar       Sensor
 1     Bad Temp   Sensor          5    Bad Rad Term  Computation
 2     Bad Sun    Sensor          6    Bad Wind Term Computation
 3     Bad Hum    Sensor          7    Bad ET        Computation


                         Appendix G3

        Leaf Wetness Data/Status byte in the LOOP packet

     The Leaf Wetness Data/Status byte in the GroWeather's LOOP
data packet contains both the current Leaf Wetness Data and
whether or not Leaf Wetness is enabled on the console. If the
Leaf Wetness sensor is enabled, the lower nibble of the Data/Status
byte contains the current data (0-15).
     The value of bit 6 tells whether the Leaf Wetness sensor is
enabled. This bit can be tested by masking (bitwise AND) the
Data/Status byte with 0x40. If the result is non-zero (0x40),
then the Leaf Wetness sensor is enabled. If the result is zero, then
the Leaf Wetness sensor is disabled and Soil Temperature is enabled.


                         Appendix E1

       Alarm Bit Definitions for the Energy EnviroMonitor

     These tables list the alarm bits for the Energy
EnviroMonitor. There are 2 different sets of bit assignments. One
is the set available on the Link in the sensor image. The second
set is the bits sent to the control module:

                      Alarm bit definitions

   Bit    Alarm           Bit     Alarm       Bit     Alarm
   Number Function        Number  Function    Number  Function
   0      Time            8       Wind Chill  16      Not Used
   1      Temp-Hum Index  9       Wind Speed  17      Not Used
   2      Dew Point       10      User 1      18      Not Used
   3      Reserved        11      Daily Rain  19      Not Used

   4      Air Temp - Low  12      Not Used    20      CM Status
   5      Air Temp - Hi   13      Not Used    21      CM Status
   6      Hum - Low       14      User 2      22      CM Status
   7      Hum - Hi        15      Barometer   23      CM Status

               Alarm Output module bit definitions
           Bit    Alarm Output     Bit    Alarm Output
           Number Module Function  Number Module Function
           1      Barometer        9      Hum - Hi
           2      User 2           10     Hum - Low
           3      Not Used         11     Air Temp - Hi
           4      Not Used         12     Air Temp - Low

           5      Daily Rain       13     Reserved
           6      User 1           14     Dew Point
           7      Wind Speed       15     Temp-Hum Index
           8      Wind Chill       16     Time

                             Notes:
     User 1 and User 2 are two user controllable bits that can be
       set through the PC.
     CM Status is a one nibble code that describes the status of
       the communication link between the control module and the
       weather station.
     Reserved is a bit reserved by Davis Instruments for future
       use. (for example to control a radio transmitter or solar
       powered battery charger)

    The Alarm Output Module assignments given above match the pin
numbers on the AOM board. Besides numbering from 1 instead of 0,
the order has been reversed, since the first bit sent ends up in
the high order position of the AOM's shift register.


                         Appendix H1

       Alarm Bit Definitions for the Health EnviroMonitor

     These tables list the alarm bits for the Health EnviroMonitor.
There are 2 different sets of bit assignments. One is the set
available on the Link in the sensor image. The second set is the
bits sent to the control module:

                      Alarm bit definitions

 Bit    Alarm           Bit #  Alarm               Bit #  Alarm
 Number Function        Number Function            Number Function

 0      Air Temp - Low  8      Time                16     Barometer
 1      Air Temp - Hi   9      Out Temp-Hum Index  17     UV Dose
 2      In Temp - Low   10     Dew Point           18     Wind Chill
 3      In Temp - Hi    11     Temp-Hum-Sun-Wind   19     Wind Speed
                                   Index

 4      Out Hum - Low   12     Daily Rain          20     CM Status
 5      Out Hum - Hi    13     In Temp-Hum Index   21     CM Status
 6      In Hum - Low    14     Not Used            22     CM Status
 7      In Hum - Hi     15     UV Index            23     CM Status

               Alarm Output module bit definitions
          Bit    Alarm Output        Bit    Alarm Output
          Number Module Function     Number Module Function
          1      UV Index Hi         9      In Hum - Hi
          2      Wind Chill Low      10     In Hum - Low
          3      In Temp-Hum Index   11     Out Hum - Hi
          4      Daily Rain          12     Out Hum - Low

          5      Temp-Hum-Sun-Wind   13     In Temp - Hi
                 Index
          6      Wind Speed Hi       14     In Temp - Low
          7      Out Temp-Hum Index  15     Air Temp - Hi
          8      UV Dose             16     Air Temp - Low

                             Notes:
     User 1, User 2, and Reserved bits are not available on the
       Health Station
     CM Status is a one nibble code that describes the status of
       the communication link between the control module and the
       weather station.

    The Alarm Output Module assignments given above match the pin
numbers on the AOM board. Besides numbering from 1 instead of 0,
the order has been reversed, since the first bit sent ends up in the
high order position of the AOM's shift register.

