Shutter Control Relay - No Logic Tab

Guys, can someone explain why the Logic tab is not included in the GUI for the shutter control relay? While we now have the logic engine in its various incarnations, the logic channels are still very useful, and reduce the ammount of code the logic engine is then required to run.

 

There are no logic functions in the Shutter Relay because of the special way the unit handles various C-Bus levels. If logic were added to the unit then you're effectively putting a layer of ambiguity over the top of what are already special cases. We'd all get hernias trying to figure out what the unit was actually supposed to be doing.

Far better to put that logic in a PAC or C-Touch where you've got all the logic in one place and you can clearly predict how the unit will behave.

 

Logic is not compatible with the 'level translation' mode of control that can be used for shutter relays. In 'level translation' mode, a number of group levels near the limits of the range are reserved to have special meanings so that for example, repeated broadcasts of the same level by a key unit can achieve an open / stop / close / stop cycle. If this level were to be combined with the level of other groups, operation would be hard to predict. At best, one could achieve an enable / disable function, but at worst, the shutter position would appear to not be related to any of the groups logically combined.

While the proportional mode of the shutter relay could make sensible use of logic, this is not the preferred mode of operation as it then places demands on the matching of the failsafe time to the ramp time in any ramping commands that are issued to control the shutter position.

So to keep things simple, logic has not been included in the shutter relay.

 

more details here

http://www.cbusforums.com/forums/showthread.php?t=4125