Building a reliable mesh

Topic Progress:

The communication mesh

Nero devices communicate with each other using the Z-Wave Plus protocol. The Z-Wave Plus protocol is a self healing mesh network, meaning that if you move devices around they will discover their new network location and rebuild their pathing information. The way you build your mesh at the beginning can impact how smoothly your entire installation proceeds.

Reliable pairing

Pairing and configuring your Nero device is the most sensitive time in the devices communication life cycle. There are a lot of messages exchanged including some critical security messages that don’t retransmit well. To ensure you get the best pairing performance and the most stable mesh we recommend you use a long extension lead and bring the gateway to each device to pair within 1m.

You can access the Web UI via the factory IP when connected to the built in WiFi AP when moving the gateway around.

There are 2 ways to start pairing mode for your gateway, the pairing wizard and the physical buttons. In most instances you will want to use the pairing wizard so that you can name and assign the device to a room but the physical method can be convenient in cases where you don’t have a web browser available.

Network Wide Inclusion

If you have done the course previously you will know that we used to recommend Network Wide Inclusion, starting in the centre and pairing outwards in a spiral. This is no longer recommended. As the Z-Wave spec has evolved the security requirements have been significantly improved, the side effect being that NWI is no longer a reliable way to build a strong mesh.

  1. Navigate to the pairing wizard and select your device from the list.
    HINT: As you become more familiar with the Nero range you can skip the wiring diagram pages of the wizard by selecting Other Nexus Device from the list.
  2. Wait for the blue bar to appear and say “Add new devices now…” and initiate pairing on your device. Pay attention to the speed that the 3 actions are in the video, going too fast will not be detected properly by the device. When using a toggle switch remember to turn the switch on and off three times so it is detected like a momentary switch.
  3. After a few seconds the device will be detected and configuration will begin. Allow up to about 90 seconds for this to complete and take you to the last page of the wizard.
  4. Set a name for the new device and assign it to a room. If you don’t have any rooms created yet select >>Add new room and enter the name. The device and room will both be created for you.
  5. Allow the device to finish configured and the interface to show a fully formed device view. Once the spinner has disappeared change the state of the light from the switch and ensure that the gateway is receiving reports. Once that is confirmed try controlling the device from the UI and confirm the device changes into the expected state.
  6. Configure any parameters you require for this device. We recommend you always limit the energy reporting frequency even on small network.

To ensure the most reliable mesh build, always ensure a device is fully operational (the testing steps mentioned above) before continuing to the next device. This way you reduce the chance that pairing messages get caught up in other network traffic and fail to fully configure a device.

Add in battery devices

Once you mesh is built you can begin adding in your battery powered devices. When pairing battery devices we recommend always performing the process close to the gateway, within about 1-2 metres, and then taking the device to the final location after the process has finished. It is not uncommon for pairing to fail if the devices are too far away even if there is a strong mesh between. the gateway and the battery powered device.

Always remember to label your battery powered devices, especially reed sensors! If the end user decides to recharge several devices simultaneously there is a high likelihood they will not be returned to the right position if they are not labelled. Remember to ensure you place your label on the device itself and not on the mounting hardware that can be separated from the device.

Moving or removing devices

Z-Wave devices build up a list of routes they can take through the network to reach the controller and other devices. This is referred to as the neighbour list and is built when the device interacts with devices around it and during the pairing process. When you move a device to a new location (such as after pairing it near the gateway) or you remove a device from the network this list may become inaccurate.

Thankfully Z-Wave Plus is very clever with routing! The next time the device tries to interact with the network it will notice that its previous best route is no longer available and make requests to the network to discover what is around it and what the best route is now. This also happens when the gateway tries to talk to a device, if the device doesn’t respond it will ask the network to send locator messages to establish the route.

What impact does this have?

When routes aren’t up to date and have to be corrected you are likely to notice delayed reactions (a device takes longer to turn on or off) or delayed reports (it takes longer than usual to report a door opening or closing). These impacts are only temporary though and are generally resolved within minutes. On a large system it may take up to 30 minutes or so to completely correct all stored paths.

You can help speed this process along by interacting with the device at its new location, such as pressing the Sync/Service button or turning the device on/off from the input. This will cause it to go and re-establish those paths.