1-Wire

A guide to installing and configuring the 1-Wire Extension

CONTENTS

TECHNICAL DATA

  • Connected with Loxone Link
  • 1x 1-wire Interface (5V output max 50mA)
  • 16.3 kbit/s
  • Supports 20 sensors
  • Unlimited number of iButtons
  • Dimensions: 35.5 x 88 x 57 mm (2 TE)
  • Power consumption approximately 30mA
  • Configure with Loxone Config
  • Power supply: 24VDC
  • Protection: IP20
  • Ambient temperature: 0 to 50°C

1 Wire Extension Loxone

INSTALLATION

  • Mount the 1-Wire Extension on the DIN rail.
  • Connect 24VDC power supply, but do not switch on until the whole installation is completed (We recommend you loop power through the Miniserver)
  • Connect the Loxone Link.
  • Connect the 1-Wire connector to the 1-Wire bus
  • Note: If it is the last extension, terminate the Loxone Link with a 120Ω resistor (Included with the Miniserver)
  • Turn on the power supply
  • After a few seconds, the left LED will flash green if the 1-Wire Extension is already configured, or orange if not

DIMENSIONS

1 Wire Extension Dimensions Loxone

SUPPORTED 1-WIRE COMPONENTS

1-Wire DeviceFamily CodeDescriptionDefault polling cycle [s]
DS1822
Econo 1-Wire Digital Thermometer
22Temperature Sensor
Range: -55°C to +85°C
Accuracy: ± 2°C from -10°C to +85°C
Resolution: 12 Bit or 0.0625°C
60
DS18B20
Programmable Resolution 1-Wire Digital Thermometer
28Temperature Sensor
Range: -55°C to +85°C
Accuracy: ± 0.5°C from -10°C to +85°C
Resolution: 12 Bit or 0.0625°C
60
DS18S20
Parasite Power Digital Thermometer
10Temperature Sensor
Range: -55°C to +125°C
Accuracy: ± 0.5°C from -10°C to +85°C
Resolution: 9 Bit or 0.5°C
60
DS1963S
Serial Number iButton (SHA)
18Access Control0.1
DS1990
Serial Number
iButton
01Access Control0.1
DS2438
Smart Battery Monitor
26AAD-Converter and Temperature SensorTemperature Range: -55°C to +125°C
Resolution: 13 Bit or 0.03125°C

60

Voltage VDD

Voltage Supply
Range: 0V – 10.23V
Resolution: 10mV

Voltage VAD

Voltage at the input pin of the AD Converter
Range: 0V – 10.23V
Resolution: 10mV

Voltage Vsens

Voltage at an external resistor (Rsens) for indirect current measurement
Range: -0.25V – 0.25V
Resolution: 0.2441mV
Calculation of current: I = Vsens/Rsens

This chip is used by many manufacturers as a humidity sensor. To do this, the output voltage of an analogue humidity sensor is set to the AD-Converter input pin (VAD) of the DS2438. To convert the voltage into a humidity measurement, consult the manufacturer’s formula.

Example – WireGate Multisensor “MS-THS13-BRK”:

humidity_uncompensated=((VAD/VDD)-0.16)/0.0062
temperature_compensation=1.0546-(0.00216*temperature)
humidity_compensated=humidity_uncompensated/temperature_compensation

In order to convert voltage [V] into humidity [%], use the ‘Formula’ object in the ‘Mathematics’ category in PLC.

60

Icon Exclamation Mark LoxonePlease note that a short polling cycle with many temperature sensors will slow the bus communication down, so therefore the polling cycle should preferably stay at the default of 60 seconds.

WIRING

A characteristic of one wire sensors is how simple they are to use. However, please do pay attention to the following wiring instructions to ensure you get the optimum signal transfer for your sensor.

  • When installing the sensor, use a cable with a cross section of at least 0.6mm (e.g. Cat5e).
  • We recommend a maximum of 20 sensors on one 1-Wire extension regardless of wiring topology
  • The following wiring instructions should be treated as a guide only. Depending on the environmental factors, including cable length and number of sensors these instructions can vary.

Icon Exclamation Mark LoxoneWe recommend you use data cable (Cat5e, Cat6 or Cat7), and you need to use one twisted pair for GND and data.
For longer distances or when running alongside mains cables use STP (shielded twisted pair) cable. DQ and GND should be connected using a twisted pair so the data signal is twisted against GND.

OPTIMAL WIRING TOPOLOGIES

1 Wire Bus Wiring

Bus topology

Bus topology without branches is best suited for wiring. It allows a maximum range of 350m with a total of 20 sensors.

1 Wire Bus With Stubs

Bus topology with stubs

This topology can produce similar results to the bus topology without branches. The maximum cable length is slightly reduced to 300m when connecting 20 sensors.

FURTHER WIRING TOPOLOGIES

1 Wire Bus With Long Stubs

Bus topology with long stubs

One wire installation in bus topology with long stubs is not recommended as it reduces the maximum total cable length to 100m with 20 sensors.

1 Wire Star

Star topology

Star topology is recommended only for small installations, since all the sensors are brought together at one point. The maximum total cable length is 100m for 20 sensors.

Icon Exclamation Mark LoxoneRing Topology
Ring topology is not supported in one wire installations. If the sensors are connected in a ring, then no signals are received.

WIRING A 1-WIRE SENSOR

This is a schematic diagram for connecting the one wire temperature sensor DS18B20+. The pin assignments can vary between sensors so please refer to the manufacturer’s datasheet.

Wiring A 1-Wire Temperature Sensors Loxone Config

Parasitically powered: When wiring so the 1-Wire sensor is parasitic, GND and VDD are connected together and GND is connected to the extension. Ground and data should be twisted against each other.

ExtensionDS18B20+1-Wire Temperature Probe1-Wire Temperature Probe (ordered before 2015)
(A) DQ(2) DQ(White) DQ(Red) DQ
(B) GND(1/3) GND/VDD(Brown/Green) GND/VDD(White/Green) GND/VDD

Note that not all one wire sensors can be used with parasitic power supply wiring topology. Please refer to the manufacturer’s datasheet.

Separately powered: All three pins of the sensor should be connected to the Loxone 1-Wire extension. Ground and data should be twisted against each other.

ExtensionDS18B20+1-Wire Temperature Probe1-Wire Temperature Probe (ordered before 2015)
(A) DQ(2) DQ(White) DQ(Red) DQ
(B) GND(1) GND(Brown) GND(White) GND
(C) VDD(3) VDD(Green) VDD(Green) VDD

Icon Exclamation Mark Loxone1-Wire temperature sensors can be hidden behind switch plates due to their small size. It is important that the space behind is sealed though to prevent drafts and poor readings. Because you use a CAT cable to wire the 1-Wire sensors and switches the remaining cores can be used for the switch plate.

WIRING AN IBUTTON READER

The iButton reader is connected to the Loxone 1-Wire Extension. The white wire is wired to ‘DQ’ on the extension and the grey wire is wired to ‘GND’.

The yellow wire is the common ground for both LEDs. Green = Green LED, Red = Red LED. Both LEDs can be directly driven of 24V, we recommend to use digital outputs for this.

I button Reader Loxone

Icon Exclamation Mark Loxone
If you have purchased your iButton Reader before 2015, then no current limiting resistors are built into the product and the LEDs must be driven as follows.
Green LED: Operating voltage 2.1V, current 20mA
Red LED: Operating voltage 1.95V, current 20mA

Since the iButton is the active component in the system, you can attach only one iButton reader for each 1-Wire Extension, if you want to tell which reader the signal was coming from. If you do not mind which reader the iButton has been identified at then you can attach as many readers as you wish to the 1-Wire extension. Maximum number of iButtons per reader is unlimited.

CONFIGURING EXTENSIONS

Click here to find out how

ADD IN 1-WIRE DEVICES

Select the 1-Wire Extension in the Periphery tree window, then click on ‘1-Wire Search’ in the Context tab on the top toolbar:

Searching 1 Wire Device Loxone Config'

Select the sensor in the Search results and give it a name, then click on ‘Create device’. At this point you can also assign the iButton to a particular user, by selecting it from the drop down list and clicking ‘Assign to user’. Now this iButton serial number will be displayed in the user properties.

Searching 1 Wire Device Loxone Config'

The sensor is displayed in the Periphery tree, and can now be used in the pages

Searching 1 Wire Device Loxone Config Periphery Tree

IDENTIFYING 1-WIRE SENSORS

The easiest approach is to connect each sensor one after the other to avoid confusion. You can also connect all the sensors and then change the temperature of each sensor individually to identify it using Liveview.

FIND OUT MORE

Contact us

DOWNLOADS

1-Wire Quick Connection Guide (pdf)

Find out more on Wikipedia

1-Wire EG Declaration of Conformity (pdf)

RoHS Declaration of Conformity (pdf)