PAC status after power failure

I have tried a few searches of the forums, and the only info I can find that points to details of PAC recovery after power failure is in the PICED help files "Note that the C-Touch / PAC unit itself will recover the level of all Group Addresses it uses automatically".

Can someone please confirm that group status' are regularly saved in some manner and recovered by the PAC on power restore?

The reason I ask is I need to understand this more clearly, a project we are working on now requires a GA to be ON the majority of the time.

Have people had issues with power failure recovery?

Many thanks!

 

From memory the PAC and the C-touch monochrome will update GA status on the network MMI. Without spending too much time on it the MMI is a large-ish network message initiated by an input unit (lowest unit address) and answered by output units. The MMI message has a level for all 255 GA in the application in question. They used to teach this stuff - or at least print it back in the good ol days of C-Bus. These days that sort of information is in the "under the hood" category. Anyway, an MMI is sent out about every three seconds for each application address in use. Input units and embedded devices like a PAC listen to MMI's to ensure they are all up to date.

(Experiment - get a four gang key input with four individual GA's programmed. Have the same four GA's programmed on a single output unit. Program the output unit with an area address. Turn on the four groups via the keys then "RAMPOFF" the area address. The physical channels are now off but the four keys show "ON". 1-3 seconds later the next MMI for that application comes around and hey presto the keys update to the correct off state. The magical MMI has done its thing - End Experiment).

So after a power failure the MMI will do its thing. Depending on your PAC programming you need to be careful what happens on power up after a power fail. A couple of real good tips are;
1, Always write initialise code for objects you have introduced into your programs. eg set counters, flags even important GA's to specific states. Remember the initialise code is run first on power up and is only run the once.
2. Start a counter in your initialise code, when your counter gets to a value of 5 or 10 set states of important objects. Sometimes when power is flakey it can come back on fall over again come back on etc, it can be handy at times to wait a few seconds for things to settle down....

 

OK - I simplified the MMI thing - so shoot me... At least I don't get my car stuck halfway down a set of steps in a rush to get inside a licensed premises to have a beer.

PS MMI's don't travel across network bridges...

Now for a $10 paypal voucher, what does MMI stand for ??? - No CIS or brains trust members allowed to answer...
24 hour window..

 

You are thinking of someone else

 

Many thanks for your input. It seems to me from your MMI description that those sequences resolve discrepancies amoungst GA states, however the status of GA's on power down are most likely(?) nothing related to that once power is restored?

I know that a C-touch saves GA's regularly to a file, however a PAC does not? Is this assumption correct? The help files seem to assert that the PAC also recovers GA's it uses autmomatically, however I do not see how this occurs unless they are written to non-volatile memory (flash).

The typical consensus on this forum tends to be that setting output units to restore to previous level, but input units are off on restore is understandable -- the input units will update after the MMI signals do their thing. But GA's that are not governed by output units are a different story, eg. "Night LED Level", "Stair PIR Disable" type applications that are not stored in output units.

 

Multipoint to Multipoint Instruction.


Took a while to find Page 56 of the C-Bus Energy Management Manual.

 

Richo - I didn't mean to imply it was Ashleigh who parked a car halfway down a set of steps, however I can see it read that way. I was trying to indicate other people do silly-er things than cut corners on a MMI description. Come to think of it I don't have anything on Ashleigh in the silly category. The closest I can get is point out silly things his friends and colleagues have done

For the record I believe Ashleigh is a responsible driver and just as responsible when it comes to parking.

 

Hi Charlie - is that manual an old one ? (several years of more) I have one of those from when I did C-Bus training 12 years ago.

I think they stopped putting that sort of tech info in training manuals some years ago ????

PS I was only joking about the $10 paypal voucher, I don't think such a thing exists - at least I hope such a thing doesn't exist. The whole paypal thing with ebay is a bit rich ($hitty) if you ask me.

PSS You are correct of course...

 

The level of each group address used by the PAC gets stored in non-volatile memory and is restored immediately following a power failure.

The MMI mechanism described above also comes into play if there is a discrepancy between what the PAC thinks the state is and what the output units know the state is.

 

That's great news Darren, that means the GAs just need to be used in the PAC and they'll be restored nicely.

Thanks for your help!