Easy 1-Wire®

Using 1-wire® devices in your KNX® installation is easy:
You only need these additional items:

1-Wire Installation

    – a small computer with an installed operating system and Java-environment, e.g. a raspberry pi with a raspbian image.
    – a suiting case for rail mounting.
    ean USB-1-wire®-interface (for Linux you need one with a virtual serial interface – a FT232R-Chip from FTDI will do the job, for Windows we recommend the 1-wire®-USB-adapter DS9490R).

 

Installation – Hydra

Download the newest Hydra version from our webpage. You will find a test license in the folder.
Extract the software in a directory.

Installation – 1-wire®-Driver

  • Windows: Download the driver from this website and follow the isntructions of the intallation program
  • Linux: Install the driveres according to the documentation in the subfolder rxtx

Connect your devices

Please refer to this page of the manufacturer.

Configuration of the 1-wire® devices

Change to your installation directory and start Hydra with the following command:

Linux:

java -jar Hydra.jar

Windows:

Hydra

Hydra automatically finds your 1-wire® interface and lists all unconfigured 1-wire® devices in the file 1wire_unconfigured.txt. You need these information to connect your 1-wire® devices to your KNX® installation.

This is an example on how the file looks like:

Name: DS18B20, Adapter: DS9097U, /dev/ttyUSB0, ID: 2B000003BAA77828

You see a temperature sensor DS18B20 with the ID 2B000003BAA77828 which is connected to a DS9097U-Chip.

Close the program (Ctrl-C), open the configuration file 1wire.cfg and add the unconfigured temperature sensor at the end of the file.

# Sample configuration file for 1-wire devices
#
# Entries starting with , or # will be ignored
#
# Syntax (one line = one object of one 1-wire device):
#
# DEVICEID-OBJECTID GROUPADDRESS REFRESH THRESHOLD RESOLUTION
#
# Example 1:
# DEVICEID = device ID of the 1-wire device = 14000003BC7CAC28
# OBJECTID = object 0 = read object of the temperature sensor
# GROUPADDRESS = the corresponding groupaddress which will be used in a knx environment = 1/2/3
# REFRESH = time interval in seconds where the read object is read automatically = 600 s
# THRESHOLD = only sends KNX telegram in resfresh cycle when this difference value is reached (absolute value or percentage allowed) = 1%
# RESOLUTION = resolution value of a sensor (e.g. DS1820: 0.5, 0.25, 0.125 or 0.0625) = 0.25 °C
#
# 14000003BC7CAC28-0 1/2/3 600 1% 0.25
#
#
# Example 2:
# DEVICEID = device ID of the 1-wire device = AA000003BC7B8F28
# OBJECTID = object 0 = read object of the temperature sensor
# GROUPADDRESS = the corresponding groupaddress which will be used in a knx environment = 1/2/4
# REFRESH = time interval in seconds where the read object is read automatically = 900 s
# THRESHOLD = only sends KNX telegram in resfresh cycle when this difference value is reached (absolute value or percentage allowed) = 0.5 °C
# RESOLUTION = resolution value of a sensor (e.g. DS18B20: 0.5, 0.25, 0.125 or 0.0625) = 0.125 °C
#
# AA000003BC7B8F28-0 1/2/4 900 0.5 0.125
#
# Default value for threshold is 0 (send everytime), for resolution = 0.25
# 1-wire-switch-devices will ignore threshold- and resolution values
#
# ============================================================================================= #
# Put your lines here:
# ============================================================================================= #
2B000003BAA77828-0 4/2/3 900 0.5 0.125

In this example you find in the last line the configuration (all other lines are comments and will be ignored): The sensor will be mapped to the KNX® groupaddress 4/2/3 and sends the temperature value every 15 minutes with a resolution of 0.125°C to the bus when the value has changed by a minimum of 0.5°C.

Start the Program

Start the program as mentioned before. Hydra will recognize the 1-Wire® devices and connects to your IP interface of the KNX®- installation.
That’s it!

Prerequisites

  • Threedimensional groupaddresses
  • A free tunnel connection on your IP interface or a suiting router (which is capable of creating a tunnel connection). If you have an IP interface, but no free tunnel connection you can use Hydra as a multplexer. You find further informationen about Hydra on the following page

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