Lag and ST


Below is email that I sent to support. After sending, though I would post here too to see if my concerns are valid.

"Have 2 light switches setup. I tied them together using “the big switch”, so turning on/off either will turn the other off respectively. Problem is that there is a 10-15 second delay (at best). Lights are in garage and way the actual layout there is, without both lights coming on, it is dark to walk through the garage. So turning light switch on, then standing there and standing and stand and standing, waiting for lights to come on, is NOT good.

For past several weeks (more like months really) we have watched ST become less and less stable, with constant outages, constant things not working, such as scheduled lights coming on at a specific time (dusk), but never doing so. And through it all, ST just reports “fixed” when things are not being fixed and no communication is happening to the public on what is causing these issues and exactly WHAT ST is doing about them."

(Mike Maxwell) #2

While I can’t argue that there’s been some delays recently in smart app processing, quite often the issue you describe relates to device reporting.
How long does it take a physical switch activation to show up in ST?
If this isn’t happening in a half second or less, then your device(s) isn’t reporting its state changes optimally, and apps that require these notifications seem slow.
It’s helpful to understand if the issue a temporary delay in ST, or it is the device being incapable of reporting its physical state changes instantly.

(Bruce) #3

Further to what @Mike_Maxwell said, most z-wave dimmers and switches DO NOT report in a timely manner. Any apps that rely on the physical switch press will have awful lags. To get quick responsiveness, you need to use devices that have “instant reporting” (AKA the Lutron patent). One dimmer that does this is the Leviton VRMX1.

(Mike Maxwell) #4

We should really have a list of devices that support instant updates and under what conditions. We see this question over and over… For the typical HA person, they don’t know the difference, and likely the application/service will get first blame, not the actual device.

Another device that supports this are the AEON micro series of in wall modules. Having said that, the default configuration and ST driver do not…, just to add even more confusion from the casual users perspective…

(Brian Smith) #5

This is interesting. I don’t see a lag on my Linear switches. When I flip them physically, they register within half a second or less in ST. So, I take it that the Linear switches are the fast ones?

Also, the instant updates thing - is this the Lutron patent we are talking about here?

(Bruce) #6

Yes, this is the subject of the Lutron patent.


Different manufacturers have licensed the Lutron patent for specific models, not necessarily every light switch they make.

Lutron, Cooper, and Leviton have the most “instant status” zwave models.

Crestron and Control4 have them for their closed systems.

I don’t think Linear licenses the Lutron patent, but they do something with potentially much the same effect using zwave group association where the hub is included in the group. If your switches are 1 hop to the hub or you don’t have much traffic, linears could look as fast as coopers.


Brian, I think the instant response you are seeing with Linear switches (I have these) is when the switch is connected to the light or when a 3-way is virtually tied to another linear switch. But to use zwave connection to hub and an app to then trigger event, as is my issue, then there is a large lag. Is this correct in my understanding everyone?

(Erik Thayer) #9

What a ridiculous patent.


From an engineering standpoint, it’s one of the less ridiculous patents. It had real meaning when Lutron introduced it back in 93 and 97. At that time, the idea of sending information from inside a switch box seemed near impossible.

Once Lutron did it, everyone else could see how, but that’s exactly what patents are intended to protect.

It looks a bit silly now because technology has advanced so much, but that’s true of most patents near the end of their cycle. Things that seemed revolutionary have become commonplace. :blush: