1-Wire is a special protocol for device which is made by the Dallas company. Temperature sensors use DS18D20 chip. The 1-Wire bus uses 3 wire cable (+5 VCC, Data, GND) of maximum 100 m long (it is recommended to use shorter distance) and up to 32 sensors. All iSMA-B-AAC20 devices are equipped with a 1-Wire port which uses two analog outputs, AO5 and AO6.
WARNING! Before connecting a 1-Wire device to the controller, please add a 1-Wire network first. It will block the possibility of increasing voltage above 5 V and protect the 1-Wire sensor against damage.
Adding 1-Wire Network
To use the 1-Wire protocol, the iSMA_OneWire kit needs be installed on the controller using Kit Manager (see Chapter Kit Manager). Then OneWireNetwork component needs to be placed under the Drivers folder.
Note: If a 1-Wire network has been added to the controller, the AO5 and AO6 are blocked for the 1-Wire type and cannot be used otherwise, for example, as regular outputs. This restriction cannot be changed manually.
Discovering 1-Wire Sensors
The 1-Wire network has a discover action (under right-click). This action will automatically search and detect all sensors connected to the bus. It will also create a discover folder and place all found sensors there. All sensors have a unique address assigned by the manufacturer (slot Address). There is also a Description slot to describe sensor function / place using max. 20 characters. All sensors components can be moved and grouped in OneWireFolders (folders must be also placed under the OneWireNetwork component).
Adding 1-Wire Sensors Manually
To add a sensor manually, the OneWireThermometer component needs to be moved from the iSMA_OneWire kit palette and be placed under the OneWireNetwork. Then sensor address needs to be entered and the application must be saved. If the connection and address are correct, the Status slot should have the Ok value, and the Out slot should show sensor temperature given in Celsius degrees.