Max Current Draw And Connected Devices

[Driller]

The output of the PSU in my panel is rated at 1.4 A or 1.0A Grade 2. The 2 aux +'s together are rated at 500mA, the Bell12V + 500mA and the Bell and strobe triggers rated to sink 500mA each. Adding up the current draw of the control panel(120mA) SAB (15mA quiescent, 425mA sounder, 110mA strobe) the internal sounder (250mA), 4 PIR's (12mA each=48mA) and the RPK/keyprox (90mA nominal) I get a total draw of 1058mA. I'm not looking for grade 2 certification particularly so I'm tending to think this is OK. What do you think? The other bother is that since the bell trigger can only sink a max of 500mA, the 425mA drawn by the SAB bell plus the 250 drawn by the internal sounder goes over this. Obviously I can connect the 12+ input of the internal sounder to the Aux+ which solves that problem but there is only one Bell trigger. WHat about using the strobe trigger to trigger the internal sounder? Not very elegant is it...

[Service Engineer]

The actual standby current is perfectly ok, the panel will not be supplying the slightly over current 1058mA unless in full alarm.

Can you not switch either the external bell or internal siren to be SCB instead..?

[arfur mo]

The output of the PSU in my panel is rated at 1.4 A or 1.0A Grade 2. The 2 aux +'s together are rated at 500mA, the Bell12V + 500mA and the Bell and strobe triggers rated to sink 500mA each. Adding up the current draw of the control panel(120mA) SAB (15mA quiescent, 425mA sounder, 110mA strobe) the internal sounder (250mA), 4 PIR's (12mA each=48mA) and the RPK/keyprox (90mA nominal) I get a total draw of 1058mA. I'm not looking for grade 2 certification particularly so I'm tending to think this is OK. What do you think? The other bother is that since the bell trigger can only sink a max of 500mA, the 425mA drawn by the SAB bell plus the 250 drawn by the internal sounder goes over this. Obviously I can connect the 12+ input of the internal sounder to the Aux+ which solves that problem but there is only one Bell trigger. WHat about using the strobe trigger to trigger the internal sounder? Not very elegant is it...

tbh, for your needs the simplest way to measure accurately what your system draws is to place a decent DVM on DC amps and in-line with one lead the fully charged (at least 24 hours) standby battery, then switch off the mains from your part 'p' compliant and certified spur (using all safety compliant operations and procedures when dealing with such potentially lethal power levels).

you can test 'quecient current' and 'in alarm' system draw in this way, and from these results calculate if you need additional psu's or standby batteries.

i hope that helps, if so please explain it back to me as i was merely trying to protect myself from anguscanplay

regs

alan

[Guest anguscanplay]

you should be able to save some with a different internal sounder - seems high to me?

[barooga]

tbh, for your needs the simplest way to measure accurately what your system draws is to place a decent DVM on DC amps and in-line with one lead the fully charged (at least 24 hours) standby battery, then switch off the mains from your part 'p' compliant and certified spur (using all safety compliant operations and procedures when dealing with such potentially lethal power levels).

you can test 'quecient current' and 'in alarm' system draw in this way, and from these results calculate if you need additional psu's or standby batteries.

i hope that helps, if so please explain it back to me as i was merely trying to protect myself from anguscanplay

regs

alan

Arfur,

Pay attention

I know have invaded France ocassionally, but not in recent times.

So, Part P??

[Driller]

Greetings and thanks for the replies.

The actual standby current is perfectly ok, the panel will not be supplying the slightly over current 1058mA unless in full alarm.

This did dawn on me after a bit of thought but then when it goes to alarm and goes over, that's when the problems might come up?

Can you not switch either the external bell or internal siren to be SCB instead..?

Yeah I considered this too. My SAB has this facility (so you can have several external sirens I imagine)but I'd like to avoid if at all possible so as not to put a (theoretical) strain on the battery.

tbh, for your needs the simplest way to measure accurately what your system draws is to place a decent DVM on DC amps and in-line with one lead the fully charged (at least 24 hours) standby battery, then switch off the mains from your part 'p' compliant and certified spur (using all safety compliant operations and procedures when dealing with such potentially lethal power levels).

you can test 'quecient current' and 'in alarm' system draw in this way, and from these results calculate if you need additional psu's or standby batteries.

Ooh I like that. It not only sounds like fun (I am warped) but also that seems a very efficient way of testing the system....but! even if I found the actual current draw to be within tolerances, knowing that the theoretical draw is over means I would like to find another solution. BTW I did indeed fit a 3A fused spur at no more than 2 meters from the control panel.

you should be able to save some with a different internal sounder - seems high to me?

That's what I thought! And I could change it but it means going back over to blighty to get one because over here they take the absolute Micky with prices for stuff...that and baby Driller wants his alarm system now! heh, heh

The specs do say max output 1.4 A. How important is the grade 2, 1.0A bit? Surely that doesn't have any physical effect on the system, it's for certification? As far as the 500mA max on the bell trigger goes, I have just remembered I have an 8 zone expander on the system. If I programmed one of it's 4 outputs to be a bell trigger, could I connect the internal sounder to this thus relieving the main bell trigger of the extra burden?

[Guest anguscanplay]

This is one for arfur really

the trigger doesnt power the external sounder so you dont need to add that 425ma figure into the 500ma max draw - never measured it at the trig terminal ( but will do tommorow) but it`ll be tiny

[Driller]

This is one for arfur really

the trigger doesnt power the external sounder so you dont need to add that 425ma figure into the 500ma max draw - never measured it at the trig terminal ( but will do tommorow) but it`ll be tiny

Ah. Well that's the proof that you can only go so far trying work things out by (twisted) logic, I'd just assumed that it would be the same since the current was being "sunk" to the trigger. What do you think about the 1.4A versus the Grade2, 1.0A issue Angus? ( And Arfur/everyone)

Driller

[Guest anguscanplay]

Ah. Well that's the proof that you can only go so far trying work things out by (twisted) logic, I'd just assumed that it would be the same since the current was being "sunk" to the trigger. What do you think about the 1.4A versus the Grade2, 1.0A issue Angus? ( And Arfur/everyone)

Driller

bearing in mind it doesnt need to comply with any standards I`m familiar with - how long would it take to get someone to site if the power went off ? weighing up battery standby against power required it`ll not be an issue

[kka]

then switch off the mains from your part 'p' compliant and certified spur

tee hee