Z-Wave Associations. What are they and how do they differ from Scenes?
Z-Wave devices such as the MultiSensor 6 are often used to trigger automations, which can come in one of two forms; Scenes and Associations. Most of you will be familiar with 'Scenes', as they're the more commonly used method for creating an automation - if you're not, I recommend checking out this post to learn how to set up a simple scene, as we'll be setting up an 'Association' with the same functionality. That is, to have a light turn ON when motion is detected.
But first, let's take a look at exactly what our system does when our motion detector senses motion and turns ON our light. While both Scenes and Associations will achieve this outcome, they do so in different ways. Let's step through the two approaches.
- The MultiSensor 6 detects motion.
- A ‘detects motion’ message is sent to the Z-Wave controller.
- The controller checks for any additional conditions.
- If all conditions are met, the controller executes the scene.
- The Z-Wave enabled light turns ON.
- Success message is sent back to controller.
- The MultiSensor 6 detects motion.
- It sends a "Basic Command" (ON) directly to the Z-Wave enabled light.
- The Z-Wave enabled light turns ON.
- The light turns OFF when motion hasn't been detected for defined period of time (which is set in Motion Sensors 'no motion' configuration parameter).
Note: The key difference is that Scenes are executed by the Z-Wave controller, whereas the "Association" is executed directly between the Z-Wave devices (bypassing the Z-Wave controller).
Scenes VS Associations
Looking at the above processes, we can see the main difference is the Z-Wave controller. Scenes rely on both the triggering and action device communicating with the Z-Wave controller, whereas Associated devices directly communicate with one another (device-device communication). Now you may be wondering why we don't just use Associations for everything and rid ourselves of the controller?
The answer is that Associations only allow you to use predefined 'Basic Command' blocks, which restrict their use to simple functions that are typically discrete (binary) in nature. You can use a motion sensor or a button to trigger a device to turn ON or OFF or have an alarm sound when a device has been tampered with. You cannot, for example, have the colour of an RGBW light change based on various conditions (which you can easily do with Scenes).
Note: You will need a Z-Wave controller to setup your Associations.
Comparison of a Scene & Association
Scenes on the other hand leverage the power of a controller and enable you to configure even the most complex of automations. Continuous parameters such as temperature and lux can be used to trigger events. An array of additional conditions including time, or multiple device parameters can be used to constrain the triggering of a scene, and actions such as the sending of push notifications can be setup - these more intricate automations cannot be done with Associations.
Note: A list of available functions that can be used to Associate your device to another can be found in the Z-Wave Alliance catalogue.
When to use a Scene or Association
Based on the pros & cons shown in the above table, I typically use Scenes to bring my automations to life. They’re more powerful, easier to set-up & keep track of and you have the option to turn them ON/OFF as you like. Associations are on the other hand are more difficult to keep track of and cannot be switched OFF. They will continue to trigger the automation until the Association has been removed from the triggering device.
Associations however do have there place, especially in mission-critical applications as they eliminate a single-point of failure. Say you want an automation to trigger in the event that your controller is offline or damaged (you want your smoke detector to trigger a sprinkler system even if you’re hub is on fire) then Associations are your friend. In some instances, typically when the devices are far away from the hub (or if the hub is cloud-based), Associations may trigger faster than Scenes, however significantly increased speed is not guaranteed for all cases.
If you'd like to learn more about Associations, check out this article.
Setting up an Association
With the background information out the way, let's dive in to setting up an Association for Fibaro's Home Center 2, Vera's UI7 and Homey. There are only 2 things to keep in mind.
- Associations are always set in the triggering device.
- If your device is battery operated, you'll need to wake it up.
- Keep the ID of the device you'd wish to trigger handy.
- Your device will always have an Association to your Z-Wave controller (Node 1). Do not remove this.
Finding the MultiSensor 6 Association Capabilities
The first step is to find the Association capabilities of our Triggering device. This can be found either in your devices User-Manual, Engineering Spec sheet or my favourite option, the Z-Wave Alliance catalogue.
1. Locate your device in the Z-Wave catalogue.
2.Select your device by clicking on its name.
3. See what Association options are available.
Creating Z-Wave Associations.
Jump to instructions for...
Associations in Home Center 2
1. Setting up an Association in Home Center begins at the devices page. Locate the device you'd like to trigger the automation and click the 'spanner' icon, outlined in red.
2. Select 'Advanced' and scroll down until you reach the 'Associations' heading.
3. Click 'Setting Association' to bring up the Associations menu.
4.0 Select the Association Group with the function you'd like to use (found in the devices Association List). In the case of the MultiSensor 6, Group 1 refers to PIR motion.
4.1 Select the device you'd like to turn ON when motion is detected. In this case, it's a lamp located in the bedroom. You can Associate these devices by simply clicking the check box next to 'Lamp'.
5. Set the 'no motion' parameter to the amount of time you'd like 'Lamp' to stay ON once the motion sensor stops detecting motion. I've set it to 10 seconds for testing purposes, but 120-180 seconds is more practical. Don't be left in the dark!
Associations in Vera
1. Associations in Vera begin at the devices page. Locate the device you'd like to trigger the automation and click the 'more' icon outlined in red.
2. Select 'Device Options' to bring up the Associations menu.
3.0 Manually add in the Association Group ID. In the case of the MultiSensor 6, the only available ID is 1.
3.1 The group may not be visible, so REFRESH THE PAGE! You may have to navigate back to this menu from Vera's dashboard.
4. Click 'Set' and add in the ID of the device you wish to trigger. In our case, the Lamps ID is 40.
5. Add in the 'no motion' configuration parameter to adjust the automatic turn OFF time. If you are unsure how to do this, check out how this article on adding configuration parameters. Remember to SAVE CHANGES.
Associations in Homey
Associations in Homey begin on the Device Page.
1. Locate the device you'd like to trigger and navigate in to advanced settings to find it's ID. In this case, the SmartSwitch 6 is of Device ID 10 will be used to control a lamp.
2. Cite the device ID.
3. Locate the triggering device. In this case, it's the MultiSensor 6's motion function.
4. Click the gear icon in the top right corner to open settings.
5. Select advanced settings and scroll down to Associations.
6. Select the Assocation 'Group 1'. It will have the value 1, which is the controller. Simply add a comma and the ID of the device you'd like to trigger. Make sure there is no space between the comma and ID.
7. Find the 'no motion' turn OFF time and adjust. This is the time that determines how long the lamp will stay ON when no motion is detected.
I hope this post has helped clarify the differences between Scenes and Associations, and that you now have an understanding of how to set up Associations within your Z-Wave system. They are a little tricky to understand at the start, but I found with a little persistence, they begin to make sense.
If you have any suggestions or are still a little confused, please feel free to leave a comment or question below and I’ll clear it up as soon as I can :)
All the best.