Three way switch - weird behaviour

[mangler]

I have figured out how to avoid this problem, but would like to understand whats going on.  

 

I have a couple of 2477D dimmers that I have wired in where a three way switch was setup.  I have only added one of them to the load - the other is just connected for communications.  They were each individually added to my ISY994 - the control switch worked fine to control the load - the other did nothing.

 

I connected them both to a scene as controllers.  Seemed to work fine (they worked on my previous ISY99i for a couple years.

 

The problem: for some reason the slave stops working, which I think is caused by anytime I try to operate the scene from the slave switch via ISY.  The "control" switch works even from the ISY - and the scene works - but if I try to operate the slave from the ISY, it seems to operate independently.  As long as I DON'T operate the slave switch from the ISY - all works fine.

 

I am sure there is an explanation that you all know - but I don't yet.  Thoughts?

[stusviews]

When you control a device from the ISY, only that specific device responds, but none of its links do. That's good. Otherwise, you could easily create an infinite loop. Here's how:

 

Switch A controls switch B and switch B controls switch A, a typical 3-way configuration. So, you turn on switch A which tells switch B to turn on which tells switch A to turn on which tells switch B ...

 

The correct way to control the devices is use only the scene.

[PurdueGuy]

What do you mean by "operate the scene from the slave switch via ISY?"   Do you mean you are just clicking "on" for that device, and just that devices turns on?

If so, things are working exactly as designed.

 

From ISY, to operate a scene, turn the SCENE on or off.  Individual devices will respond to ISY, but no scenes will be activated*.

 

*If you have programs setup with triggers like "If Status..." then program will run, and do whatever they are programmed to do.

[mangler]

Thanks guys ... from both replies, this is exactly what I am seeing.  I guess I just didn't expect that.  I figured when I turned the slave switch on from the ISY - the scene would get fired.  Also - it wasn't obvious to me that the scene wasn't getting fired when I turned the load switch on from the ISY because the light comes on.  

 

I get it now and understand.  Appreciate the quick replies.