I was experimenting with groups and scenes App. Apart from providing nice way to group devices in logical clusters it doesn't seem to do much more. In the case of a large ZWave group when you turn on that group it still launches a barrage of unicast commands to each unique device. I was hoping to find some sort of multicast scheme to lessen hub traffic.
Is there a way to send a multicast command to several devices rather than discrete unicast commands for ZWave? I am thinking this is something not supported in ZWave? Is there any work around to effectively create a multicasting capability?
I have always been a fan of ZWave but the popcorn effect is annoying for large device turn on/off rules.
I did see Zigbee seems to have some sort of grouping scheme to enable multicasting to the group. Anybody using that and does it work well? Does it reduce Zigbee traffic?
I have used Zigbee group messaging, which is available in both Groups and Scenes (Groups) and Room Lighting. It does reduce traffic, as it sends only a single command from the hub, not one per device. I have also suggested this to many users who have problems doing things other ways. From these experiences, I can say it tends to work better.
Neither app supports anything like this for Z-Wave (or any other protocol) -- so for other devices, as you note, it's just sending a series of commands. In Groups and Scenes, you have the option for "metering," which can be used to insert extra spacing between commands if you find that the speed at which they are sent out is causing problems. While it pretty much by definition increases the "popcorn effect," the increased reliability may be worth it.
Z-Wave JS technically supports multicast, so adding this to the hub in the future (for the C-8 Pro if running JS) might be possible, though!
As @bertabcd1234 notes, Zwave Groups/Multicast are part of the Zwave Spec (and it's also part of the Matter spec). But getting it to actually work, is a different story. It's definitely supported on the ZwaveJS stack (not sure about ZIP), but there were issues until V7.23 of the SiLabs FW. So HE would definitely need to add support for this feature, and you would likely new to be running the ZWJS stack with more recent SiLab radio FW (for a while V7.24 was released, but it got pulled back).
And HE doesn't support this in Matter either (to my knowledge) - But it's called "Group Messaging" and a subset of the spec is: Technical Documentation
All of these talk about elimination of "popcorn lighting effects" - So at the moment, all three protocols support this, and HE just implements this on ZB.
Once can always hope for the future (I'm waiting on the Matter implementation, but I'll take any additions, including ZW for shades, at this point)
I experimented with this today. It seems adding these metering delays improves the end to end execution of the All Off/On rules. I found the sweet spot was between 75 and 90 msec so I locked it down for 90 msec. Results are still inconsistent with end to end rule run times but they see to avoid some of the stumbling that occurs when there is no metering. On average times improved.
Is there a reason why the dimmer section of groups only lets you turn on/off the dimmer to the last set value? I would prefer to enter a value to set to instead.
You might also want to look into Room Lighting, which combines Group and Scene functionality into a single app that can do that and more and allows creating an activation table with different settings for each device if you want.
Yes when you create a group of on/off light switches and dimmer switches you can only control this group from a rule with an on/off. That's ok for switches but for dimmers an On means return to prior dimming level. In my case I want to dim to 100% regardless of what prior level was.
The calling rule just issues an On of Off command to the group.
As an experiment I created a group with only dimmers. Then I created a test rule seeking to Set Dimmers and Bulbs/Set Dimmer/my_dimmer_group/Set to 100%..
The dimmer group did not show up in the list of available dimmers. Only individual devices showed up.
I presume this is a conscious aspect of the group app but it's not obvious to me why. Ideally I could create two groups switches and dimmers then call the switches to turn on and then call the dimmer to set to 100%. That doesn't seem possible the way thing work currently. I wonder what the complexity is for not allowing that?
Anyway I'll take your suggestion and look at room lighting. I've avoided it for now as it seemed overly complex for just controlling lights. Time to roll up my sleeves and get over the initial learning hump.
I understand what you mean now! This isn't really the case, however -- it depends what type you chose for the group when setting it up, the Select group device type option. This can only be selected when initially creating the group, so you'd need to make a new one if you've already done that, but selecting "Dimmer" (which gains you level control) or "Bulb" (which gains color/CT control in addition to level) are your other options; it sounds like yours was set to "Switch" (on/off only).
