Sample Code
and Programming Reference
Updated: January, 22, 1999
Documentation is provided free of charge and "as is."
Davis Instruments will provide support via e-mail at support@davisnet.com. We will not answer
questions over the phone. If you have a question, please consult the files contained in
this package, especially the frequently asked questions in the file "faq.txt".
If you cannot find answers to your question in "faq.txt," check the web site for
an updated version. If you still cannot find answer(s), you may submit your questions by
e-mail. Please explain in as much detail as you can what you are having difficulty with
and if possible include a copy of the source code section that is in question. We will do
our best to answer your questions within a week. If the questions you have are lengthy or
complicated, Davis Instruments is available for PAID support in one hour segments at
$100.00 per hour.
This documentation provides the information and materials needed to
write custom applications for Davis weather stations and the WeatherLink. The current
version of this documentation supports all of the weather stations manufactured by Davis
as of 1/98 (these are: the Monitor II, Wizard II & III, Perception II, GroWeather,
Energy, and Health stations).
Documentation is provided in both MS-Word 6.0 (.doc) and ASCII
(.txt) file formats. The information contained in one format of a particular file is
identical to the information in the other format. Please read the Technical Reference
("techref.txt" or "techref.doc") file before doing any programming.
The Technical Reference describes each command the WeatherLink data logger understands,
which are the same commands our WeatherLink Software uses. It also contains many tips and
examples of how to use the commands effectively. Included are a series of "C"
and Basic source code examples using the WeatherLink commands. We've included source code
we have used to exercise the interface. With careful study it should answer questions the
technical reference does not. The included source code makes calls to the commercial
package "C ASYNCH MANAGER 5.0", and can not be used to make an .exe file without
this library.
If you are programming in BASIC, look at the Visual Basic code (16
bit) in "comm.bas" which illustrates how to use the "LOOP" command. We
suggest if you are after real-time weather data that you use the "LOOP" command.
The commands outlined are a combination of ASCII and binary data,
can be sent out any RS232 serial port and used to extract from the weather station any
data that the station displays (current conditions, highs, lows, etc.) as well as archive
data from the WeatherLink.
NOTE: Davis Instruments is not responsible for any damages resulting
from use or misuse of the information on this disk.
What will this disk do for me?
This library contains the necessary information to enable a
programmer to write custom programs using Davis weather stations and the WeatherLink. This
consists of libraries documenting commands, source code example.
What does this disk contain?
readme.htm - This file contains an introduction and explanation of
the contents and organization of the Serial Communications Reference. The contents are the
same as the contents of this page.
techref.txt - This file contains a technical description of the
RS232 interface. It describes the primitive commands upon which all higher level
functionality must be built. It also contains may examples of "C" code fragments
to illustrate how the commands are used. In addition, this file contains tables of the
station and link memory addresses. techref.doc - MS Word version of techref.txt
appendix.txt - This file contains descriptions of coded numerical
and bit-mapped values. appendix.doc - MS Word version of appendix.txt
faq.txt - This file contains short answers to may commonly asked
questions. faq.doc - MS Word version of faq.txt
database.txt - This file contains a description of the database file
formats created by the PC Link, GroWeather WinLink, Energy WinLink, and Health WinLink
software sold by Davis Instruments. database.doc - MS Word version of database.txt
commands.c - This source was included to give you a source code
reference of the commands in action.
serial.c - Example "C" interface to the chip.
serial.h - Header file for serial.c functions.
ascii.c - Converts a binary weather data file to ascii form.
ccitt.h - Tables used for the CRC checksum calculation.
thitable.h - A table for calculating Temperature- Humidity Index
from temperature and humidity data.
For Visual Basic Programmer's look at the source code in COMM.BAS
which illustrates how to use the LOOP command and decode the data packet sent back from
the weather station.
COMM.BAS - BASIC source code using loop command. Visual Basic
programmers should look at the source code in COMM.BAS which illustrates how to use the
LOOP command and how to decode the data packet sent back from the weather station.
- CRC.DAT - Data file with tables for CRC calculation.
- FORM1.FRM - Project file.
- FORM1.FRX - Project file.
- VB_LINK.MAK - Make file for VB_LINK.EXE.
- VB_LINK.EXE - Compiled version of COMM.BAS.
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Additional Information