Karizma + Fault

[MrHappy]

"Do you have enough current for all your equipment?"

Yes, the Karizma's internal supply feeds all the usual alarm accessories.

Depending on what products you have the 3 sab's you mentioncould use the systems total current rating of 1.5amp when in alarm

[Oxo]

Depending on what products you have the 3 sab's you mentioncould use the systems total current rating of 1.5amp when in alarm

As I mentioned

So, in your expert opinion.

What happened in the power outage?

Not as clever as you think are you, not an insult. A fact.

[james.wilson]

op i see how your disable switch now works.

Wont cause an issue as such imo

But i do feel you are overloading it, not the cause of this issue probably. But hat is the current loading in day and alarm?

If you have dodgy mains then you can fit various filter depending on the issue or use a decent ups between supply and panel.

[Roger99]

Good morning gents. Thanks for your comments. All very interesting.

Our mains here is no more or less reliable than in most places, but over the years there have been a few dropouts. The Karizma has always gone through them without a problem, but on this occasion it locked up. I can only speculate as to why it happened this time. It may have been a surge on the mains when it went off or back on, or perhaps it's an indication that the panel is about to fail, which is why I was asking for advice on a possible replacement. But that has nothing whatever to do with my special SAB switching.

Regarding possible overload by the SABs. When I installed the system I did check the current drain on the panel under various conditions. I don't remember the figures now, but at the time I was satisfied that it wasn't going to overload. It hasn't ever blown any protective fuses.

And no it does not have a mains filter. I have one to protect my computers (I work from home), and I suppose I could take a feed off it to run the alarm as well. I haven't yet installed a UPS. I could do so but I'd be concerned about the additional point of failure as they are not totally reliable. Incidentally the battery in the alarm panel is the maximum size that it will take, and it is replaced every five years. .

Happy to answer any further questions.

[james.wilson]

you need to load test your battery and id be amazed if your panel isnt overloaded. Id check it to confirm however i agree its realted to this issue. Also the fact the fuse hasnt blown is irrelevant. Depending on duration and fuse type a fuse can carry twice its rated load without blowing.

Also day mode current may be relevant.

But panels can crash especially as they get older and interference around increases etc. It has stayed the same and the world has changed around it. Id do same basic checks and if all are ok (ac on the dc side, tx output, current in day and alarm, charge voltage, battery load test etc) then id not worry too much about it

[Roger99]

Thanks. That's good advice and has made me think.

I'm certain that the currents were in spec when I originally tested them. But I replaced the SABs some time ago when they were time expired and I must confess that I didn't re-test, thinking that one type was very much like another. It is possible of course that the replacements may take more current. I'll re-check.

[Roger99]

Incidentally I notice someone picked up on my comment about interference to radio based alarms from 4g cellular.

The regulator Ofcom is under pressure from HM Treasury to maximise the profit from selling off the spectrum, and is therefore down-playing the possible interference effects. They have issued a study to justify this. Various RF engineers including myself are not convinced by this.

You might want to look at the following, and then Google '4G SRD interference' to read about the issues.

http://stakeholders.ofcom.org.uk/binaries/consultations/award-800mhz/statement/lte-coexistence.pdf?utm_source=updates&utm_medium=email&utm_campaign=lte-coexistence

http://www.rfdesignuk.com/LTEbulletpoints.htm

[MrHappy]

interference to radio based alarms from 4g cellular.

IF the 4g network has interference issues with radio with alarms I'm safe in the knowledge that replacing the radio components is liable to be cheaper for the client than their I-phone "x" which is liable to be the likely cause.

now I could buy or rent a 4G simulator to test our existing radio products but how "real world" is it going to be ?

[Roger99]

The interference will not be only from the portable phones, but also from base stations that will usually be further away but will radiate far greater powers and be transmitting continuously rather than intermittently like the phones.

As for replacing the radio components, first you have to find suitable alternative spectrum.

Read to the end of this

http://www.rfdesignu... report v2.pdf

edit. I didn't answer your question.

Any form of simulation will only indicate a general situation. It won't cover the many, many different installation variations.

[Oxo]

It seems to me that they are more worried about 862 not 868. However it was an intresting read.

For some info certain makes run with agility hopping. Runing a cycle 50 times a second or there abouts. So I think it will not be hit too hard by 4G if at all.

Your new sounders may have more current draw than you suspect and the tests as James mentioned are well worth undertaking.