¶ How to Build Your Z-Wave Mesh (or: Keeping your Z-Wave Mesh Happy)
If you use Z-Wave devices, your Z-Wave mesh is the backbone of your home automations. This mesh network is the way Z-Wave devices communicate with each other and with the Hubitat Elevation hub. Z-Wave devices build this communication mesh automatically, but it is not instantaneous. You MUST give your Z-Wave mesh time to establish itself before automating your Z-Wave devices. Automating devices too quickly can lead to frustration with routing issues. It may take several hours for your Z-Wave mesh to automatically find the optimal routing. While Zigbee devices can automatically self-heal, that feature only came into existence for Z-Wave devices with the introduction of Explorer Frames, which are intended to add similar self-healing options. For an Explorer Frame to reach its target, a number of compatible repeater nodes must be present. The specific number depends on the actual network topology and the amount of RF noise in the environment.
To maintain successful communication, all Z-Wave devices must be accessible. If you add devices near the Hubitat Elevation hub, then move them to their final location, you may experience routing issues down the road; therefore it is preferable to join your devices in their intended permanent location. Z-Wave radios operate from 865.4 MHz to 926.3 MHz, depending on which country you're in. Interference from WiFi or Zigbee devices is not an issue because they both operate in the 2.4 GHz frequency range, but devices such as baby monitors, cordless phones, etc. may cause signal interference because they operate in the same 900 MHz range,
A single Z-Wave network can support up to 232 devices, with up to 4 hops, therefore the total home coverage will depend on the amount of mains powered Z-Wave products on the network. The maximum range with 4 hops is roughly 600 feet (or 200 meters). Having one or more Z-Wave repeating devices will help strengthen the ability of your Z-Wave devices to maintain communication with the hub. Your environment, the distance to the furthest device, obstructions and device performance will determine the number of repeating devices required. A Z-Wave repeating device is one that is plugged into an outlet or powered by mains voltages. Battery powered Z-Wave devices do not repeat signals. Non-repeating devices are known as end devices, whereas Z-Wave repeating devices are routers.
Follow these procedures when discovering your Z-Wave devices to establish a strong Z-Wave network. Please be patient, as it is key to success. Once you have added all of your Z-Wave devices, the network will be very busy. Give your Z-wave mesh network time to settle. The waiting is the hardest part, but your patience will be rewarded with a reliable mesh network.
¶ Discovery (Z-Wave Inclusion)
If you have prior experience with another hub, you may be familiar with the term inclusion. This is where a Z-Wave device joins the network, and the process differs slightly from Zigbee devices, which are said to pair with the hub or another device in certain circumstances. However, with Hubitat Elevation, the process of joining a Z-Wave device to the hub is almost identical. A primary difference from the way Zigbee and Z-Wave devices join a network is actually in the way they leave their former host controller, as explained in the next paragraph about Z-Wave Exclusion. See Add Device for information on how to join your Z-Wave devices to Hubitat Elevation.
¶ Z-Wave Exclude
Unless it is a brand-new device, Z-Wave devices must be excluded from their previous hub before they can join a new hub. Ideally you should also perform a factory reset before attempting to join devices to the new Z-Wave network. If the procedure to factory reset is not available, then you should at least perform device exclusion. To do this you will need to open up your old hub UI and follow the Z-Wave exclude procedure. If you are unable to access your old hub, you can still perform a general Z-Wave exclusion from Hubitat Elevation, even though the device has never been joined to your Hubitat Elevation hub in the first place. Anytime you want to remove a Z-Wave device, it is important to run a Z-Wave Exclude first. The process is different between device manufacturers, but generally involves pressing a button or initiating a sequence of steps on the device after putting the hub Z-Wave radio into exclusion mode.
¶ Force Remove
Occasionally, you may end up with a device that was sold, given away, has ceased to function properly, or you forgot to exclude it, and now you no longer have an opportunity to exclude it from the hub. Whenever possible, you should always remove a device properly using the Z-Wave Exclude function of the hub, but if that isn't possible due to extenuating circumstances, you can force the system to remove the device. If a device is Force Removed from the hub, a so-called "ghost" node will remain that does not appear in the Z-Wave Radio Devices list but may wreak havoc on your Z-Wave network.
¶ To try to properly remove a Z-Wave device from your network
- Navigate to Devices, then navigate to the device's device page.
- Take note of any apps listed in the “In use by” section on the device page, and remove the device from these apps to avoid potential problems with these apps.
- Select Remove towards the bottom of the device page; a popup will appear indicating the hub is in exclusion mode for this device (node).
- Place the Z-Wave device in exclusion mode (follow the manufacturer's instructions).
- Within a few seconds, you should be automatically redirected back to the Devices page. This indicates successful exclusion. If not, the popup will remain visible, and if the exclusion does not complete, you will eventually be offered the option to Force Remove. Use this option only as a last resort. For example, you should first verify that you have properly placed the device into exclusion mode according to the manufacturer's instructions.
¶ To force-remove a Z-Wave device
- Follow the steps above, and if the exclusion does not complete properly, you will be offered the option to force remove as indicated in the last step.
- Note the “Device Network ID” or “DNI” of the affected device before removing it (this is the Z-Wave node ID in hexadecimal). This can be found on the device page under Device Information or in the DNI column in the Devices page.
- Once a device has been removed from the Web Interface, it will be automatically removed from the Z-Wave radio. It is not necessary to use any external tools to manipulate the Z-Wave radio to try to remove it on your own. (There are rare occasions where a node remains on the radio and is not removed. A reboot of the hub will typically allow the system to remove the node during the next scheduled cleanup, or you can do so manually per the below if you have the Z-Wave node ID of the device or can otherwise identify it in the table.)
¶ To remove a device from the Z-Wave radio
This is generally necessary only for “ghost nodes,” incomplete inclusion attempts, and other problems. A proper removal or force-removal as outlined above should be attempted first if a device is listed under the Device column in the Z-Wave Details table. To remove a device from the radio directly:
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Navigate to Settings > Z-Wave Details.
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Find the desired node (device or row).
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Select the Remove button from the Status column. If you do not see this option, try Refresh once or twice (waiting several seconds or longer between each attempt). If Remove still does not appear, the hub is likely able to hear back from the device, and it can be either properly removed (see above) or factory reset (see manufacturer's instructions) and this process re-attempted. It can also be excluded (via a general exclusion) using another hub/controller, including a different Hubitat Elevation hub or any controller, if one is available.
¶ Z-Wave Repair
Each Z-Wave device builds a neighbor table to keep track of which repeaters are its closest neighbors. When you initiate a Z-Wave repair, you are telling each Z-Wave device on the network to re-establish which routing devices are its closest neighbors, and therefore the most efficient route back to the hub. This also tells each device to forget about router devices that no longer exist on the Z-Wave network, or are now out of range and no longer able to be used for routing.
Z-Wave Plus is designed to not require repair, and will “self heal.” There is no magic behind this process. Z-Wave repair merely re-creates routes for nodes on your mesh. It is generally unnecessary to manually repair Z-Wave Plus devices thanks to Explorer Frames. However, it can occasionally help to run repairs on a Z-Wave Plus network to reduce the time required to update the neighbor table.
Model C-7 hubs allow a per-node repair from the device/row in the Z-Wave Details table in addition to the hub-wide Z-Wave repair option offered on all models. The per-node repair is preferred when possible.
NOTE: Running a Z-Wave Repair will not revive failed devices.
WARNING! Z-Wave repair is very network intensive since every device will be re-routed. We do not recommend running Z-Wave Repair if you are not currently experiencing delays or issues with your Z-Wave network.
¶ What happens during a Z-Wave repair
- The Hubitat Elevation hub will run a quick assessment of your network and create a repair plan that organizes the nodes for repair. This process maximizes efficiency and helps to reduce potential failures that occur when no routes are available to reach a node. Nodes closest to the hub are repaired first and the process moves outward hop by hop.
- NOTE: Only mains powered devices can be repaired.
- Once a node is selected for the start of repair, the hub will send a No Operation (NOP) command to determine if it is reachable. If the node is reachable the hub proceeds to the next step, but if the node cannot be reached it will be marked Failed and the hub attempts to reach the node again.
- The hub will request that the node look for new neighbors. During this process, the node will ping all nodes in range and report back to the hub.
- Additional Static Update-Controller (SUC) return routes back to the hub, are assigned based on the updated internal routing table the hub maintains.
- The hub then requests additional routes assigned to the node for each virtual node ID assigned to the hub. This maximizes request and reporting efficiency.
You can find details on mesh performance expectations from this Silicon Labs training module.
¶ How Z-Wave Repeaters Work
A Z-Wave repeater or router, is a messenger that relays information, until the messages between end devices and the hub have reached one another.
Z-Wave repeaters are devices that will always be powered by mains voltages. A Z-Wave outlet is an example of a repeater acting as a relay point for devices that are too far from the hub to reliably send and receive signals. Z-Wave and Zigbee are two different wireless protocols, therefore a mains powered Z-Wave device can only function as a repeater for other Z-Wave devices, and Zigbee devices only act as repeaters for other Zigbee devices.
NOTE: Devices too far from the hub or obstructions will result in dropped connections from weak Z-Wave signals.
When a repeater is placed between the device and your Hubitat Elevation hub, the device communicates with the repeater and the repeater communicates with your hub, significantly improving performance and reliability.
Repeaters can communicate with other repeaters, to form a strong and resilient Z-Wave mesh network.
Non-repeating battery-powered devices must always have a parent to talk to, either Hubitat Elevation or mains powered repeating devices. When the device first joins the network, it will choose a parent that provides the strongest Z-Wave signal and store it in the neighbor table. Once a device chooses its parent, it will hold on until it absolutely cannot communicate with it, even if a different parent with a stronger signal is introduced into the network. Not all Z-Wave devices can select a new parent, but using Explorer Frames, some can. However, the automatic process of updating the neighbor table to keep track of the strongest neighboring repeater devices, can take several days to complete in a large Z-Wave network. For this reason, initiating a Z-Wave Repair can help reduce the time required to update the neighbor table.
¶ Tips for designing your Z-Wave mesh
Although a Z-Wave mesh has the capability to automatically establish the optimal path for devices to communicate with your hub over time, there are some design recommendations you should follow to optimize the network and achieve the best possible results.
- Z-Wave is a low-powered, short-range wireless protocol. Locate your hub as central to your home as possible. This will allow signals to spread around your house with minimal obstructions between your hub, any routing devices, and your end devices. Avoid the corners of your home, basements, garages or locations with substantial concrete, pipes and other large metallic objects that may cause signal interference. If your router is in a corner of your home, take steps to get your Hubitat Elevation hub centrally located in your home, using either a long Ethernet cable or Powerline Ethernet adapters to convert your home electrical wiring into a communication path for Ethernet devices. WiFi adapters are also supported on model C-5 and later but require additional hardware (not included) and is considered beta functionality at this time.
- NOTE: Older Z-Wave locks may require you to have the lock and hub very close together to join them. Locks that support Network Wide Inclusion (NWI) should not require this if there are Z-Wave repeaters nearby.
- A single Z-Wave network can support up to 232 devices, with up to 4 hops, therefore the total home coverage will depend on the amount of mains powered Z-Wave products on the network. The maximum range with 4 hops is roughly 600 feet or (200 meters). Having one or more Z-Wave repeating devices will help strengthen the ability of your Z-Wave devices to maintain communication with the hub. Your environment, the distance to the furthest device, obstructions and device performance will determine the number of repeating devices required. A Z-Wave repeating device is one that is plugged into an outlet or powered by mains voltages. Battery powered Z-Wave devices do not repeat signals.
- When installing several devices, install Z-Wave mains powered repeaters first, beginning closest to the hub and working outward so other devices will be able to use them to reach the hub. Once the Z-Wave routers are installed, add your battery powered Z-Wave end devices.
- Building construction and materials can alter the Z-Wave signal and its ability to penetrate obstructions, thus making the effective range shorter. Signals may pass easily from one side to the other of a room where there aren't any obstructions, but a single wall depending on its construction, could significantly weaken a signal. Changing device location or adding repeaters can significantly improve this situation.
- Metal completely blocks Z-Wave signals. Do not install your hub in metal racks or boxes.
- Stubborn Z-Wave devices or those that are suddenly orphaned from a previous hub that has failed, may put up a fight when you try to join them to a Z-Wave network. It can be helpful to power cycle your device, perform a Z-Wave Exclude, followed by a factory reset to fully prepare the device to join its new Z-Wave network. Some light switches have a small tab to pull out, commonly referred to as an air gap (but note that certain older GE switches do not disable power to the internal Z-Wave radio when the air gap is pulled; cutting power at the breaker may be necessary for these devices). Try this for at least 30 seconds before attempting a Z-Wave Exclude and the discovery procedure again. See above for more tips.