Here is how it works: Every event in the Caséta system generates a Telnet message from the SmartBridge Pro. Hubitat would receive that event, and fire an automation from it -- for example turning on the other switch. The Hubitat automation would send the command to the Lutron SmartBridge via Telnet, and the SmartBridge would signal the light to turn on.
The central portion of this is the timing from the bridge to Hubitat and back to the bridge. In ST this portion is bridge to Lutron cloud, Lutron cloud to ST cloud, ST cloud to Lutron cloud, and Lutron cloud to bridge. It should be obvious that there will be a timing advantage on the local Telnet portion.
However, there is one other factor: I'm pretty sure (but can't test at the moment with Caséta) that the Caséta dimmer itself does not report 'on' to the bridge until it has finished it's ramp up from 0 to the set dimmer level. This introduces a lag for both ST and Hubitat, and in Hubitat would be the dominant source of lag, far exceeding the Telnet roundtrip timing. It is probably not possible because of this to get the response time of the second switch to less than a second --> perceptibly not instantaneous.
Ironically, the response time in Hubitat for a Lutron Pico button press to turn on a light is on the order of 70 to 100 msecs, perceptibly instantaneous. Your example, because of the dimmer, would be slower.
You will find generally, that the Hubitat Lutron integration is super fast and rock solid reliable, just like Lutron itself (thanks in part to Lutron's telnet implementation being virtually instantaneous). It is not possible to beat local communication and a fast hub cpu. Hubitat elevates Lutron, makes it do tricks it otherwise is incapable of.
I have part of my house on RadioRA 2. There are automations I use where a Lutron keypad press, which in the Lutron system will turn on a scene with several loads, is intercepted by Hubitat during the ramp up of those lights, and the destination dimmer level changed by Hubitat. This is completely seamless. What you see is the lights ramping normally to whatever the level is, but unseen is a sophisticated automation running simultaneously deciding what level they will be set to depending on the time of day (or could be depending on luminance).
So I'm the only one who notices a second or two of delay on my Pico remotes on rare occasionans, especially if either that particular remote (or perhaps any Pico at all) hasn't been used in a while? Or maybe it's just the first time after the hub boots, even if that's been a while (does it only re-establish the telnet connection on first use?). I haven't quite figured out a reason yet. I also don't know if it's Pico-to-Bridge delay or Bridge-to-Hubitat delay, and I don't think Lutron provides a good way for me to see. (It could also be my automation, but it's just Button Controller, which I don't think should magically get better after the first button press, but again, I haven't figured out a pattern.)
In any case, they are normally quite fast, and I'm only talking about the Pico remotes--I've never used the hardwired switches or dimmers. The remotes are great to use as button devices in Hubitat for any purpose, and they're so cheap that even with the Bridge they'll eventually pay for themselves compared to the cost of Z-Wave or ZigBee buttons if you have enough, plus they mount and blend in very easily (like a standard switch if you want).
Are they switches or dimmers? Lutron does not report the change of a dimmer going on for 3 seconds. This by design. So HE will not know about the switch going on for 3 seconds, then the rule to turn on the other is very quick.
So, to clarify - I can add Pico remotes and use them for any purpose with Hubitat? So I could theoretically replace my Lutron Connected Remotes (they're a pain) with Picos and use them to trigger any device through Hubitat?
Yep! You can use a Pico (through the Bridge Pro) on Hubitat for any purpose--it can control any device Hubitat is able to "speak" to, since you can use button presses (or releases or holds depending on the driver you choose) as triggers that can then do whatever you want.
I happen to be using all of mine for lights at the moment (Hue lights) but plan to eventually use one for some fans (on smart switches and one with the canopy ZigBee controller) and maybe HSM.
PS - You may still want to keep the Lutron Connected remote (even if you don't use it) if you ever decide to pair Hue bulbs directly to Hubitat rather than using the Hue bridge--the Connected remote is one of few ways to "reset" the Hue bulbs if they join to a ZHA network and get set on a channel ZLL (which the Hue bridge needs) doesn't use.
Agree with hanging onto the Connected Bulb Remote (at least one). If you have many, you can probably pay for your Lutron Smart Bridge Pro with the sale of the Connected Bulb Remotes you don't need. They fetch a handsome price on Ebay is seems.
@blanghor You can even control music with standard Picos (e.g. You don't need the special music version unless you care about the engraving on the buttons). @stephack uses them this way and has customized his ABC app specifically to make this scenario easy to setup.
Cool. Yeah, I'll hang on to at least 1 LCBR and may just keep all of them as long as they work. They're kind of a PITA to get working correctly with SmartThings so the possibility of gradually replacing them with Picos makes me happy. It will also kickstart my migration from ST over to Hubitat.
It's my birthday today and the wife has been nagging me about what I wanted as a gift, so I emailed her a link to the Lutron Pro Bridge. Hopefully I get it this weekend.
I have 6 LCBRs myself, 5 are still in use actually. I have mine paired to both my Hue Bridge and certain bulbs around the house like bathroom, closet lights, hall light. Places where I just want simple control of the lights and still have control of the lights from Hubitat via the Hue Bridge integration.
The LCBR buttons cannot be programmed with the Hue Bridge or HE, but are just not "stolen" away so that both the Hue Bridge and the remotes can control the light(s). Here's where first learned about that trick. I then later bought one of the Trådfri bulb and bridge kits when they first came out just to test what was possible and came to discover that's essentially how their entire system works. Played around with ST and the Trådfri remotes and then wrote how to do essentially the same thing with a ST hub, which at the time gave you more control over the Trådri bulbs than IKEA'a own bridge did. I'm fairly certain you could do similar with HE if you wanted to. They would pair as "Device" here, instead of "Thing".
I started out with the LCBRs on Wink, where you can program the buttons, but they were always terribly slow and unreliable in that configuration. As simple remotes paired directly with the Hue Bridge and Bulbs though, they're rock solid. Still, I wanted the control I had with Wink, just not the problems and that's when I first learned about what was possible with the Smart Bridge Pro, and @stephack 's ABC. So I wrote a post about how to configure that on ST and that led me to discover Hubitat and their far superior built-in integration with the Lutron Smart Bridge Pro, with no dependency on a cloud. Ordered an HE the next day.
So for me, LCBR are fine for doing those simple tasks and I do the fancy stuff with my Pico remotes. The one next to my bed for example controls the bedroom light ON/OFF and dimming, the lower dim button turns one bulb on to low with a singles press, the middle button locks all the doors, the button button turns off the lights upstairs with a single press and holding the bottom button runs my goodnight sequence.
Does Lutron have a On/Off switch that doesn't require a neutral wire connection like the PD-6WCL Dimmer switches?
I'm wanting to replace several dumb wall switches that power ceiling fans, which I currently have Hampton Bay Controllers on and Hampton Bay states not to put that load on a dimmer switch and I don't have neutrals at these boxes? Pretty much the only use these will have is for in the event is needed to power cycle off the fan.
However, this won't work for your needs because the way the non-neutral switches and dimmers work is by leaking small amounts of current to load.
Can I make a suggestion? Since you going to wire the fan to be always on, why not use a Pico remote in place of a Caseta switch? Pico remotes can be mounted in gang-boxes using a special mounting plate that Lutron sells for about $5.
I currently use rule machine to automate the fans, I rarely ever need to manually control them, if I do I can use the provided RF remote or the Dashboard to do so.
They were solely going to be used to "if" the power needed to be cut without having to flip the breaker also to have matching switches throughout the house. The Pico's will only serve one of those purposes.