Z-Wave Device Initialisation
One of the common questions, or one of the common themes at least is a misunderstanding of how devices are included into the Z-Wave network, how they are then discovered, and how the device database is used. This article will provide some information on the different steps that are undertaken, and what happens along the way...
There are, in general, three main phases in the initialisation of a device into a Z-Wave network before it is usable by the software. First is the network inclusion, second is the device enquiry, and finally is the device configuration. The image below provides a summary of this, and also how the database is used.
During the network inclusion phase the device is included into the network by the controller. The controller must be put into inclusion mode, and the device must also be put into inclusion mode. The controller will then allocate a node number for the device, and this node ID is then used for all subsequent communications. The controller records the device information within its memory, and this information is always available when the home automation software communicates with the device. It is not possible to change this node ID, and if the device is excluded from the network, and re-included, a new node ID will be allocated.
Once a device is included into the network, the home automation software (e.g. openHAB) can start to discover what services the device provides. OpenHAB will first request information about the manufacturer - the manufacturers ID, and also the device identifiers. The manufacturer ID is a unique number the identifies each manufacturer, and each manufacturer identifies its devices by two further numbers - a device type, and device ID.
During the configuration phase, the devices internal parameters and association groups can be configured. This generally uses the database since the information about each parameter can not be read from the device itself.