How to add a secondary controller for Zwave binding?

Hello all!

I am inexperienced in this field and may ask some silly questions. Apologies for that.

I have read the term “Secondary controller” in the documentation of openHAB, but I cannot understand properly what will be the purpose of a secondary controller. Can someone please explain this to me?

Secondly, I have two raspberry pi and two Aeotic Z-stick gen5. Can I use one of them as my primary controller and other as secondary controller? If yes, how to do that?

I have been gone through some posts regarding secondary controller but lost my track every time. If some one can help me in this regard, it will be very much helpful.

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I believe a secondary controller will either be something like a remote that can control devices directly, or another dongle for cases where you have more devices than fit on one controller.

I think unless you have more than 255 devices there is no need for a secondary controller.

I don’t see why not but it’s not going to do anything for you unless you have hundreds of devices, if I understand correctly.
They are both part of the same network so I don’t think you can use a secondary controller to expand the reach of the network.

Thanks a lot for your informative reply @rlkoshak.

I have another question regarding how the secondary controller works. Does the secondary controller communicate directly with the primary controller?

Let’s think of a situation. There is a primary controller ‘P’ , a secondary controller ‘S’. And a device ‘D’. Can we create such a scenario such that device ‘D’ communicate with secondary controller ‘S’ and then the secondary controller communicate with the primary controller ‘P’?

I am just confused that how a secondary controller works, mainly how it communicate with the primary controller and devices.

As @rlkoshak correctly stated a secondary controller essentially is just a remote to (directly) control devices.
If you used it to expand the device limit it was another primary controller.
You can’t use a secondary to be a hot standby backup of your primary controller (which I assume is what you’re after, but this is an instance of the XY problem, see #8 in How to ask a good question / Help Us Help You).

Thanks @mstormi for your reply.

My actual goal is to figure out these questions actually.

  1. Why and when people use a secondary controller ( I have got an idea about that)
  2. How secondary controller communicate with the primary controller? Is there any direct communication or they don’t communicate( works like separate controller). In this regard, I am still confused.

Of course there sometimes is communication between controllers but it depends on the use case.
Your question still sounds like XY to me. Why do you want to know, what do you want to achieve with that knowledge ? If you want to understand Z-Wave on theory level, there’s better resources on the Inet.