Opposite of AND in Logic on hardware

Is there anyway to implement the opposite of AND without prgramming logic.

When Aircondition group is on the exhuast fan should be off, but when Aircon is turned off then the exhuast fan group should be set to on.

This has been implemented in logic in the wiser however i feel there may be a better approach.

 

It would depend on what input unit you have controlling the devices, on an eDLT you could implement scenes and use the scene cycle feature.
Logic in an output unit wouldn't achieve what your after.
Also are you sure you don't want any condition when both devices are off, maybe when on holiday or cleaning the equipment. Scene cycle could achieve this.
The wiser logic is reliable and not really that complicated.

 

Thanks Wonky, i was thinking that maybe the logic in the wiser may be causing the issue the issue with the Wiser playing up after a few months, hence removing the logic. There is a acontrol to turn the exhaust off, I though of a scene however this is a big install with a lot of scense and a number of the EDLTS are already full.

I have login running in my Wiser that has not caused any issues so it was a long shot.

 

Check here under logic forum, you should look for a module that controls the fan when the light is on/off and keeps it running for x seconds after it goes off. I've seen a lot of this type, mainly for the toilet but also for halls and outside lights, driveways as well.

 

You could get the current cbus fan relay to operate a changeover contactor and use the normally closed contacts to control the fan.

Logic in the Wiser is easier though

 

Just remember that if wiser restarts for whatever reason all groups and IO's will be in the off state (in Wiser only) this may cause problems with unwanted things occurring. Under initialisation in logic you can set groups and IO's to a required state at start up.