Alarm Backup 3,5V iso 12V ?

[Christoph]

Hi all,Following this forum from Belgium thx to google translate ;-) , so please allow me to ask a question in English.I've got a working IHC installation, including the alarm setup. That alarm setup contains 3 Alarm Pirs, a keypad etc. Everything worked fine. Recently I finally closed the tamper circuit ('status') (that for various reasons wasn't yet fully looped). After that, the Pirs stopped responding. Analysing the problem, I discovered that the Alarm Backup module only feeds 3.5V iso 12V between pins 3 (0V) and 5 (12V). Before I had never measured the Voltage, but they operated as should, so I assume 12V was present.Measuring the other pins on the Alarm Backup give the correct Voltage back.1) Anybody an idea?2) Could I alternatively connect the Pirs to pins 6 and 7 (so directly to the battery)?Kind regards,Christoph

[Lars Jacobsen]

Hi ChristophNice to know our Danish IHC system is used out in the big world :-)Does your battery suply 12V on pin 6 and 7 ? Pin 6 must only be conected to battery minus - not 0V (gnd) If theres only 3,5 V out on pin pin 3 and 5 without anything conected (and 12V battery is OK) it seems that the module is defect and has to be repaced. Connecting PIR directly to pin 6 and 7 will work for a short period of time until the battery is drained for power. The Alarm backup module does not charge the battery (at my knowledge) but only reduce the aplied 24V to 12V at the output terminals.

[Claus Frederiksen]

As Lars writes it is only allowed to connect the battery to pins 6 and 7. The reason is that 0V on pin 6 is not at the same voltage level as 0V on pin 1/3.Perhaps you draw to much power from the module? The module only allows a power draw of 500mA on 24V circuit (pins 3 and 4) and 450mA on the 12V circuit (pins 3 and 5). The outputs are current limiting , that could explaine the voltage drop. Try disconnecting everything on pin 5, and measure the voltage again.To Lars: The module actually does charge the battery. It is stated in this user guide (in Danish): Link

[Christoph]

Hi,Thx for the quick feedback.@lars-jacobsen:Pins 6 and 7 indeed supply 12V and are only connected to the battery. @claus82:I will verify the power draw as there are quite a number of elements connected. The Pirs indeed stopped functioning after the tamper circuit was closed (so brought under tension 24V, but this circuit is not drawing a lot of current doesn't it?). I'll post my feedback tomorrow.If indeed the Backup module is recharging the battery, it would be OK to connect the Pirs to pins 6 and 7. Even if the 0V is different between pins 6 and 3, as long as I wire the relevant pair of pins, the Pirs are fed with 12V. Could any of you confirm this (in theory :-) )?Please also not that the 12V LED on the front of the module is giving a steady green ...Kind regards,Christoph

[Lars Jacobsen]

Hi' date='If indeed the Backup module is recharging the battery, it would be OK to connect the Pirs to pins 6 and 7. Even if the 0V is different between pins 6 and 3, as long as I wire the relevant pair of pins, the Pirs are fed with 12V. Could any of you confirm this (in theory :-) )?[/quote']In theory yes, but thats only if the connected circut does not share the 0V. And most PIR does share it between the input power and the output signal. So no go in this situation. If the output from the PIR was an isolated no/nc contact then yes. But sinse it share its gnd/0V power and uses it as referense for the output signal then i dont think it will work properly. I think it must be as Claus mentions - drawing to much current. You can calculate it with this:http://www.lk.dk/download/software/backuptidsudregning_30062006.xlsstill in Danish :whistle: :silly: :pinch:

[Claus Frederiksen]

If you use Alarm Pir 120C, it actually has a separate NC contact, as most alarm PIR's do. But that would mean you would have to have 2 separate 0V wires to each PIR, one from pin 6 to the supply of the PIR, and one from pin 3 (or input module) to the NC contact set.Worse is, that LK do not specify the charging current (max current on pin 6+7), and it is probably less than the 450mA on pin 3+5. (LK specifies the modules max powerdraw to 790mA - which in theory only leaves 65mA charging current (790-500-(450/2)))

[Christoph]

Yes, it works again! 12V on pins 3 and 5!How did I do this? Not sure ... but here's what I did:1) Powering off power supply (so only drawing current from the battery) leaving only the 12V LED green on the module. No difference in values measured, so 24V on 3 & 4 and 3.5V on 3 & 5.2) Powering on again. No difference measured.3) Decoupling all contacts from pins 3 & 5. (I know, should have done this sooner ... instead I decoupled everything from 3 & 4 before in an attempt to lower the current drawn) 4) Rewiring all contacts to pins 3 & 5. (It is actually only one wire from the backup module itself to a connector from where different wires go to the seperate devices)5) And hey! 12V between pins 3 & 5.So two options here that can explain:1) internal Alarm Backup trouble ...2) wire badly connected ... Thx for the program to calculate the current drawn. I will nevertheless still verify.The alarm PIRs attached do indeed have a dedicated NC contact. So it's isolated (I presume) from the controlling part of the setup. Happy regards,Christoph