Relay Recovery

Hi guys,

I'm not sure if this thread belongs here or in software section, but here is my question.

We have a commercial site where only relays are going to be installed and they are going to be ON all the time during normal power. When the power fails and the shop switches over to generator, we would like the relays to recover to OFF state and then start up in sequence to reduce inrush current. This will also mean a saving on the size gennie.

The problem is that, when tested, it seems to me that the relays revert back to their original state before power failure for about 3 seconds after power cycle, before actually switching to the programmed recovery state. How do we get past this problem as it will not work in this particular installation?

Thanks
Brodsky

 

Its possible you have an Input Unit set to recover these groups to their previous levels.. Check the PowerFail tab of Input units that have these groups..

The 3 seconds is the time it takes for an "MMI" to be kicked off by an Input Unit and for this process to resolve the conflict between the input units and output units..

 

C-Bus DIN Rail relays are latching type relays. That means that they preserve their state even when no power is present. The unit needs to power up and initialise before it can do anything about that and it takes 5 seconds.

 

Do I understand correctly that there's nothing we can do about this?

Thanks

 

The only way I've found is to use the single and 2-channel relays, that are non-latching. We've used them for dropping out non-essential supply contactors but not ideal for controlling all lighting in the building.

 

Thanks dimmerguy,

I'll check this out, wasn't aware that these relays don't latch.

Thanks