Z-Wave® Terminology and Technical Overview

Z-Wave is a wireless (RF) home automation technology that's available worldwide. There are several characteristics of Z-Wave technology that we think are important for users to understand. In this wiki article, we'll attempt to explain these features in terms that our users will find easily understood.

This page is about the Z-Wave technology in general terms: if you're ready to get started using Z-Wave with Indigo, check out the Connecting Z-Wave Interfaces of the Getting Started Guide and the Managing Your Z-Wave Network page.

Overview

Z-Wave is a wireless mesh network technology. That is, all signals are transmitted over RF (for those with power line-based systems, no more signal noise problems from stuff plugged into the wall). Z-Wave is a proprietary technology, owned by Sigma Designs, and licensed to a variety of vendors. The Z-Wave Alliance was formed by various vendors to help assure interoperability between devices.

Z-Wave is a mesh network - where each node knows about the ones around it so that a message can be sent through various devices on the network until it reaches its destination. This increases network and message reliability.

Z-Wave devices operate on different frequencies, so you'll find devices specific for North America (908MHz), Europe (868MHz) and Australia/New Zealand (921MHz). Many vendors supply devices for each so finding devices in your area shouldn't be a problem.

Controllers

If you are an existing Indigo user, specifically one who uses INSTEON, you may recognize the term “controller” to mean a device which can control other devices: KeypadLinc, RemoteLinc, SwitchLincs, etc. You can link a controller directly to a “responder” such that when a button is pressed on a keypad or switch, a command is sent directly from it to the linked “responder” device. Z-Wave has a similar mechanisms (Associations and Scenes) which we'll discuss in a bit.

However, Z-Wave uses the word “controller” differently.

Primary Controller

The Z-Wave primary controller is responsible for assigning network id and node ids to devices (Z-Wave devices are referred to as a “node”) and to create Secondary Controllers. This controller is the one that keeps the definitive list of nodes on the network. There must always be a primary controller in any Z-Wave network. For Indigo controlled Z-Wave networks, the primary controller will be the Z-Stick - it will create the network id (or home id) and will assign node id's to any device that's added to the network (see Building a Z-Wave Network below for more details on how to add devices to the network).

Secondary Controller

A Z-Wave network can also have optional secondary controllers. These controllers will be added by the primary controller and will maintain a copy of the network. This allows the controller to also add devices to the network. The only limitation of a secondary controller is that it can't include other secondary controllers - only the primary can do that.

Controller Types

Controllers are generally one of two types. Portable controllers are handheld controllers, like remote controls, which can move around your house. Because these controllers can be at any place in the house, they must constantly be asking for nodes around it so they can maintain the routing information.

Static controllers are controllers that don't move around so don't necessarily need to update routing information very often. The Z-Stick is primarily a static controller - however, since it can be moved around to include other devices it may need routing updates more frequently. Other types of static controllers are some scene controllers (synonymous to the INSTEON KeypadLinc), some switches, etc.

Including/Excluding a device in a Z-Wave Network

When you add a device to a network via the controller, it's called “including” the device (i.e. the inclusion process). Each device may have a different inclusion process. Likewise, you must exclude a device from the network if you are no longer using it

In Indigo 7 you can usually include and exclude devices directly from Indigo. Older versions require you to take your interface to the device to include/exclude it using the button on the interface. Check the Managing your Z-Wave Network section of the docs for your version for specifics: (Indigo 7, Indigo 6).

Devices

There are Z-Wave devices of all types you'd expect with any mature home automation technology: plug-in modules (aka wall-warts), switches, outlets, thermostats, motion sensors, etc. Z-Wave also supports locks from a variety of vendors.

Z-Wave devices can implement a variety of capabilities. We recommend that any devices you get support these features when possible:

  • Z-Wave Beaming (sometimes called Security Compatible) - this will enable your network to more easily deal with locks and other security-related devices (more specifically, it's for devices that sleep but need to wake up frequently for commands). Note that for lock devices to work in a Z-Wave network, you often need Z-Wave beaming supported devices near the lock itself to communicate with the lock. Note locks must be included into the Z-Wave Controller with encryption enabled.
  • Slave Routing - this will allow devices to route messages to other nodes - so if your controller isn't in direct range of a device it can still send and receive data through an intermediary.
  • Security - this is a special capability for devices like locks that need an extra level of security.

Many battery-powered devices don't support one or both of the first two because of the need to conserve power. However, most modules that are plugged directly in to power should support beaming and routing. Some sensors support security, but that function is mostly reserved for Locks. Indigo 7+ fully supports security and locks.

Other capabilities that are often desirable in Z-Wave modules are associations & scenes, which we'll discuss next.

Associations

Z-Wave associations are used when one module needs to command one or more other modules. For example, an association with a switch module could be created to control a remote lamp module when the switch is turned ON and OFF. Associations are also used between a module and the Z-Stick used by Indigo. In that case, the association is often used so that Indigo can update its UI when a module changes states, or so that user defined Triggers can be executed when a button is pressed.

Routing and Network Healing

Z-Wave uses a routed mesh network for extending the range between all modules. For reliable communication to occur between distant modules, an established route, or path, needs to be created. Indigo tells the Z-Stick to create these routes when a module is Define or Synced. If you move modules to different locations it may be necessary to re-Sync them so that their new routes can be established. If you are unable to communicate with a distant module, then try re-Syncing modules that are nearby the distant module to help establish a new route.

Further Reading

If you want even more detailed information about Z-Wave, here are some resources we suggest:


Z-Wave® is a registered trademark of Sigma Designs, Inc. Indigo's support of Z-Wave hardware is neither endorsed nor certified by Sigma Designs.

z-wave.txt · Last modified: 2017/09/16 15:48 by jay
 

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