No Message generated from Logic Assignments??

I think the (end of) this thread explains the problem I am having but as it was a while ago I thought I'd double-check.

http://www.cbusforums.com/forums/showthread.php?t=879&highlight=logic+groups

As a simplified example: I have two GAs for two downlights wired to separate dimmer channels.

I want Light1 to turn on/off Light2 which is easily done by using the Logic tab and Logic assignments option. The problem is that although Light2 turns on/off with Light1, no C-Bus message appears to be generated for Light2 to turn on/off - there is a message for Light1. This means that input units (and Homegate,Toolkit) do no show Light2's GA as on.

Is it correct that logic assignments (within and across output units and GA's are done at a lower level, as suggested in the thread above) and that no message is generated?

If so would this mean that there is no way to determine a GAs state if controlled by another GA using Logic Assignments?

[ I know the above can be done using scenes but this requires a specific 'on' and 'off' which I'd prefer not to do. - I'm interested to know what is actually happening message-wise ].

 

You're correct. The processing of Logic is done "beyond C-Bus" as it were, i.e. within the individual dimmer itself.

Logic is not manipulating the state of the groups as such, rather it is taking the state of two groups and combining them using logic to come up with a level for the channel.

There are a few other things that manipulate the final value that gets applied to the dimmer channel. Min/Max level scaling is one. Remote Overrides are another. The dimming curves in the dimmers are another. Channel protection circuits are another.

As you say, if you want the groups to reflect the actual load state then Scenes are the best way to go. An alternative is to use a PAC. That will mean that logic won't be obscuring the final state of the load, but you'll still have the other things in the paragraph above to consider too.

 

Many thanks for the confirmation Newman. I've got a PAC so I'll look into that as an option.

Andrew