Bosch 880 - new siren installation help needed

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surfwatch

17 posts

Geek

#215218 17-Jun-2017 13:50

I have a Bosch Solution 880 burglar alarm. The outdoor unit has reported a fault in the external siren. It is one of those old metal ones. I purchaserd a new polycarbonate SS-C1, but the wires are totally different. Can any one let me know how to rewire the new unit.

The old unit has incoming wires red blue white and black. There are two tamper switches in the unit, but the new one only has one. The Bosch reports faults showing siren, light etc.

Photos of the old and new unit wiring configuration are attached.

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surfwatch

17 posts

Geek

#1802764 17-Jun-2017 20:25

I have worked out that red is the power and goes to strobe + with a piggyback to siren +. Black is the siren - and blue is the strobe - white goes to tamper. What goes to the other tamper is what gets me.

The unit specs say I could combine the strobe blue and piggy it back to the siren. The existing unit has a red going to the tamper and a white. However the new unit specs say the tamper should have a ground and an output. Maybe the white is a ground and i could then reroute the black which is an output to the other tamper.

Goosey

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#1802804 17-Jun-2017 21:26

tie both tampers together in paralell?

DarthKermit

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#1802807 17-Jun-2017 21:32

Or if the alarm board expects there to be two tampers, can you just put a jumper wire across the tamper terminals to fool the board into thinking that tamper is never triggered?

Ge0rge

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#1802811 17-Jun-2017 21:50

Looking at the circuit in the old picture, the tamper is a serial loop - the feed comes from the red, goes into the tamper switches (normally one to tell if the unit has been opened, and one to tell if it is pulled from the wall) and then back to the control unit via the white wire.

To wire the new one, you need to connect the red wire to the positive of the siren, and then jumper it to each of the other positives. Connect the other lines to the appropriate negative terminal. Bob's your uncle.

surfwatch

17 posts

Geek

#1802892 18-Jun-2017 09:54

Thanks GeOrge, I looked up the wiring diagram for the 880 system, and it would appear that the tamper is wired to the 12 volt. Also from the diagram of the old unit it would appear that the 12 volt completes the circuit for the tamper switch as well. One further question though, the new siren does not have a +ve or -ve, I suppose it doesnt matter it just completes the circuit.

Thanks I will post if it works for any one else trying it.

Ge0rge

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#1802894 18-Jun-2017 10:01

You're correct - it's just a matter of completing the circuit. The control panel is looking for a voltage drop at the tamper input (indicating a break in the line, be it someone actually tampering with the siren, cutting the wire etc). As long as there is a complete circuit, it'll be happy - don't be concerned about which way around the wires go for the tamper -the other three are important though!

pipe60

104 posts

Master Geek

#1803756 20-Jun-2017 07:57

If you have a spare core for a negative you can wire in the LED as well.

cisconz

cisconz
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#1803775 20-Jun-2017 08:52

The LED is just an indicator LED - I use mine with a 6 core cable to tell me that the alarm is set / unset - The strobe will overpower it when used so there is no point in wiring it up to the Siren output.

The Tamper ports don't need + / - as they are just 2 sides to a switch, so can be wired up either way.

Hmmmm

surfwatch

17 posts

Geek

#1804975 22-Jun-2017 08:22

Now it seemed to work, but when I connected it up the piezo siren was making a warbling sound. So I called in the installer. Only a 10 minute job.

Turns out the white cable from the power to the tamper switch is a resistor. Probably means you dont need much power to the tamper, just a connection.

Also how this was done I dont know, something was done in the box or the programming, but the system was activating a horn speaker, and the new alarm box had a piezo siren instead. May get up there one day and see what us different.

I will know next time however. Hope this helps the next person to replace theirs.

Thanks for your help everyone.

nickb800

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#1805000 22-Jun-2017 09:04

I think the idea of the resistor is that the alarm can tell if someone has just tried to short the tamper circuit. Rather than being a simple continuity test, it's looking for a particular resistance. Makes it harder to fool the sytem

Ge0rge

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#1805409 22-Jun-2017 21:12

Yup - they're called End of Line resistors (EoL). Amatuers will tend to put them at the control logic end, which completely negates the point of having them - if they are at the EoL as intended, the control logic will be able to tell if the cables have been tampered with. It's also used as a method to run two different zones on the one input of the control logic - you tell it the resistor values of the two parallel circuits connected to the one input, and it can work out from there which zone has been activated by changes in the resistance that it can see - quite simply, but clever none the less.