Weewx driver for the HP1000 (WS1001, XC0422) Weather Station using WiFi connection
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readme.md

readme.md

HP1000 - a driver for HP1000 and clones including WS1001 and XC0422

Copyright 2017 Susan Mackay

Introduction

The HP1000 driver communicates directly with the weather station console via WiFi.

When the driver is started, it will make contact with the weather station and try to retrieve any archive records (make by the weather station at the interval set by the "Interval" setup parameter) before reading the current data at regular intervals. If weeWx has not been used before, this can take a while (about an hour for each year in the archive) but it means that the weather station historical data is made avialable to weeWx.

The normal generation of html files will be delayed while weeWx performs the catch up process, but it means that the data will include the period while weeWx was not working but the weather station was still logging data.

Parameter Units

The HP1000 weather consoles can display wind, rain and similar properties using a selection of units (set in the console's "Setup" panel). For example, wind speed' can be in m/s, km/h, knots, mph and even Beaufort scale numbers. The driver will determine the currently selected units when it connects with the console

Network

The HP1000 (and similar 'clone' devices such as the WS1001 and XC0422 weather stations) communicates via WiFi to the local network to pass data to Weather Underground (or whatever other weather upload service is used). As such the weather console will have an IP address on the local WiFi network.

The driver will communicate with the weather console via this WiFi link. In order to find the weather station on the network, the driver will send 'broadcast' messages until it receives a response from the weather console. The response will tell the driver the weather station's IP address and form then on all communication will be direct between the driver and the weather station.

If communication is lost with the weather station, the above process is repeated until it is reestablished.

Log Messages

The driver will output messages to the system log as it tries to establish connection to the weather station console and if communication is lost. No messages are sent by the driver during normal operation. All messages have the text 'HP1000' in them which allows easy searching of the log file.

Limitations

Unit Selection

The driver only requests the parameter units form the console when a connection is established. Therefore, if you change the unit for a parameter, the weeWx program must be restarted. Otherwise the information form the console will be misinterpreted.

Network

In order to find the weather console, the driver issues UDP 'broadcast' messages. While it is possible for routers to pass these packets between subnets, the need to be suitably configured (which is beyond the scope of these notes). Therefore it is recommended that the weather console and the computer running weeWx and this driver be on the same subnet.

If you have the 'netifaces' Python package installed, then the driver will try to find the correct broadcast address of the "default" interface. (The default interface generally the one your computer uses to communicate with the rest of the Internet.)

If you do not have the 'netifaces' package installed then you will need to define the broadcast address mask as a configuration item in the '[HP1000]' section of the 'weewx.conf' file - it takes the form:

ip_address_mask = "192.168.1.255"

or

ip_address_mask = "10.1.255.255"

In other words, it is the main network address with '255' added as the final component or component, depending on the addressing scheme used on your computer.

The driver will attempt to communicate with the weather station as soon as weeWx requests a 'loop' packet. This means that the driver can request a packet every few seconds (depending on how fast the weather station responds to each request) which can lead to a volume of network traffic. Depending on the network setup and other uses of the network, this may or may not be an issue.

Be default the 'loop_delay' configuration parameter is set to 15 seconds which means that there will be a minimum of 15 seconds between requests for data from the weather station. This parameter can be adjusted up or down as desired with a value of 0 meaning that packets will be requested as frequently as possible.

Testing

The driver can be run stand-alone and without connection to a weather station console by following the instructions for runing a stand-alone driver in the weeW3x documentation.

Pre-requisites

The HP1000 driver has been tested using weeWx V3.6.2. It should work on earlier (3.x.x) versions but this has not been tested and is not guaranteed.

Active Network Required

An active network is required before the HP1000 driver can access the weather station console. This can be an issue when weeWx is run as a daemon which means that it will be started as the computer system boots.

weeWx can be set up to handle this situation is one of two ways.

Note Editing the weewx.conf file is the recommended option

Edit the weewx.conf file

weeWx has a built-in mechanism to handle network failures. In the weewx.conf file add in the line

loop_on_init = True

This line can be added right at the top in the same area where the 'debug' and WEEWX_ROOT parameters are defined.

In this case, the HP1000 driver will retry a network access the number of times set by the 'max_retry' driver configuration parameter (default is 3) and it will then wait for 60 seconds and repeat the process indefinitely until network access is maintained.

This process will also be used if the network access is lost at any time after weeWx is operating normally.

Edit the Daemon startup file

With this option, you tell the daemon to delay starting until an active network is available. The file you need to edit depends on whether you are using SysV or systemctl to control the computer. This can be done by editing/adding the appropriate file as outlined below.

SysV

Required-Start: $local_fs ... _$network_ ...
Required-Stop: $local_fs ... _$network_ ...

systemctl

Requires=network-online.target
After=network-online.target
Restart=always
RestartSec=60

Note: there can be multiple 'Requires' and 'After' lines in the control file.

The last two lines ensure that any crash of weeWx will cause the program to be restarted after a 60 second pause. This applies to errors other than the network access one discussed here.

Installation instructions

Please consider the information in the 're-requisites' section.

  1. run the installer:

    sudo cd sudo python ./bin/wee_extension --install /HP1000 sudo python ./bin/wee_config --reconfigure

The last command will (eventually) list all of the known drivers. Select the number next to 'HP1000'.

  1. Start weeWx: sudo /etc/init.d/weewx enable sudo /etc/init.d/weewx start

or sudo systemctl daemon-reload sudo systemctl weewx enable sudo systemctl weewx start

  1. To restart weewx:

    sudo /etc/init.d/weewx stop sudo /etc/init.d/weewx start or

    sudo systemctl restart weewx