I am considering a Honeywell Lynx system for home security and a ST hub for Automation. My question is can the sensors, assuming they are Z-Wave, be recognized by both the Lynx and ST?
As an alternative can the Lynx report to the ST?
My first foray into automation in some time. Most recently, about 15 years ago, I played around with X10. I know… showing my age…
Thanks.
Z wave devices can only belong to one network at a time, and each network can only have one primary controller.
It is technically possible to add another controller as a “secondary” but to be honest SmartThings just doesn’t do this very well as either primary or secondary. So support officially recommends against it. And they will not help you if you mess up your network by trying to make it work. 
I also find that most people don’t understand what being a “secondary Z wave controller“ means. It does not mean that suddenly both controllers have access to any information about all of the zwave devices on your account.
Instead, it means that at the time you joined the secondary controller to the network, it will get a copy of the network device table for all the zwave devices that are joined at that time, and it will be allowed to issue commands to most of those devices ( but maybe not locks and other devices using security protocols). That’s all it means. It doesn’t mean that when a switch comes on both controllers will be told that the state has changed. It doesn’t mean that the secondary will be told about any new devices that are added later. There are some systems, such as vera, which have their own software to keep all of the primary and secondary hub information in sync after the initial joining, but that’s not required by the Zwave standard, and smartthings doesn’t do that. Nor do most of the security systems that use zwave.
So your best bet is to search the forum for other people who might’ve tried it with the Honeywell system and see what their results were. It might work, it might sort of work, it might not work at all – – it just depends on some specific details of how that manufacturer has designed their platform.
Also, most security systems do not use zwave for their intrusion alert sensors—Instead they will use 345 MHz or 433 MHz proprietary protocols. They will use zwave for other home automation like light switches. It will depend on the exact model of Honeywell system that you choose, but if it is using non-Z wave sensors, those will not be able to be used with smartthings at all.
Thank you very much for the detailed explanation.
What are your thoughts on some kind of reporting from the Lynx to the ST? Or is that even possible?
I noticed that even the sensors that come with the kits aren’t z-wave. I was planning to piece out the system to ensure the zones I wanted to be double reporting would be Z-Wave. I’ll keep poking around the community to see if someone has had some success.
Thanks again for your detailed response.
To add some real-life testing to the mix:
I have ADT Pulse, which is a z-wave hub. I added SmartThings as a secondary hub about a month ago.
Both the ADT Pulse and ST app can tell a switch to turn off.
Status updates might be wonky. In the test I just did:
I got to this configuration because ADT does not expose its z-wave devices to Amazon. So the commands were clunk to turn off the light in a room. I found the steps to join ST to ADT on a post in here actually. ST also has more possibilities of future automation. Had I known how ADT was, I would have skipped Pulse.
Knowing the constraint we saw from my test, I would not do any ST automation based on z-wave switch status changes that are more likely to come from ADT. Which for me, I’m not using the ADT app unless I have to, it’s now a fallback hub. But all the other events ST can trigger on (like presence) to turn stuff on should be no problem.
Your mileage may vary
KL,
I’m wondering, on step 2. you said you opened the ST app after having the ADT turn on the light. What if the ST app was on at the time you issued that command.
Just a thought, but, it could be that the light sent out the confirmation that it was off at the time that it turned off and since the ST app wasn’t available to get that confirmation it was missed?
Your test gives some insight into how the system works, and it’s not radically different than the old X10 protocol from the little I’m seeing.
Barret
The SmartThings app doesn’t get the confirmation from the device. The device sends the information to the hub, the hub sends the information to the SmartThings cloud, the SmartThings cloud sends information to the phone app. So the phone being off doesn’t have anything to do with keeping device status is in sync. The next time you turn the phone on, it should get all of the device status information from the cloud account and be up-to-date. The problem is that the primary Z wave hub and the secondary zwave hub don’t necessarily talk to each other about any status changes. It’s not required by the Z wave standard that they do.
Also different manufactures handle these issues differently. Even differently for different models. So what works with ADT pulse might not work with Toshiba Symbio or Honeywell and vice a versa.
As long as you are paying for the Honeywell monitoring services and you get their honeywell connect app, there are some indirect integration options for cloud to cloud communications.
You can use the quick browse lists in the community – created wiki, look towards the bottom of the page for the “project reports” section, and then look on the “security” list and you should see at least one Honeywell integration discussion there.