Deltabell Plus/sound Bomb

[RossoReed]

Just installed a Scantronic 9448+ panel and Deltabell Plus to a domestic garage, and added a Sound Bomb (quad piezo) inside wired in parallel with the Deltabell (Bell Trigger and +12V), but found that the upon a Bell test, the Sound Bomb sounded OK, but the Deltabell didn't activate (The strobe activated OK).

I disconnected the Bell trigger to the Sound Bomb and the Deltabell then worked just fine, but whenever I reconnect the Sound Bomb to the Bell trigger, the Deltabell fails to sound.

 

The 9448+ panel delivers 500mA negative applied and the Sound Bomb consumes 125mA, Deltabell Plus consumes < 300mA, so power shouldn't be a problem.

 

Any ideas?

[james.wilson]

I would guess the sound bomb is keeping the 0v a little high, ie 0.7v and as such is stopping the other bell firing. 

Can you connect the sound bomb to the strobe - instead

[sixwheeledbeast]

Just installed a Scantronic 9448+ panel and Deltabell Plus to a domestic garage, and added a Sound Bomb (quad piezo) inside wired in parallel with the Deltabell (Bell Trigger and +12V), but found that the upon a Bell test, the Sound Bomb sounded OK, but the Deltabell didn't activate (The strobe activated OK).

I disconnected the Bell trigger to the Sound Bomb and the Deltabell then worked just fine, but whenever I reconnect the Sound Bomb to the Bell trigger, the Deltabell fails to sound.

 

The 9448+ panel delivers 500mA negative applied and the Sound Bomb consumes 125mA, Deltabell Plus consumes < 300mA, so power shouldn't be a problem.

 

Any ideas?

IIRC there is a 2K2 resistor required to be installed in the bell, this is covered in the manual.

[RossoReed]

I would guess the sound bomb is keeping the 0v a little high, ie 0.7v and as such is stopping the other bell firing. 

Can you connect the sound bomb to the strobe - instead

I really wanted the Sound Bomb to adhere to the program time cut-off. If I wired it into the strobe it would continue to sound and upset the neighbours.

[Oxo]

Put a timed relay on it.

Or get a PSU and a relay.

[RossoReed]

IIRC there is a 2K2 resistor required to be installed in the bell, this is covered in the manual.

 

There's no mention of it in the Deltabell's A4 installation guide, unless it's in chinese on the reverse!

But, now you mention it, I did find a 2K2 resistor in the box...

[miaren]

There is always a small datasheet in the Deltabell box detailing this exact problem.... Still got the box?

[jnealon]

Internal sounders can act up when connected in parallel with the db, resistor is meant to eliminate the feedback from db that causes this.

Can you program another output on the panel and connect the sb to this

[Oxo]

Nah the output is rated lower than the soundbomb.

One little relay job done.

[RossoReed]

guys

 

There is always a small datasheet in the Deltabell box detailing this exact problem.... Still got the box?

 

There was no other datasheet in the box, however, I've just bought a further 2 Deltabell Plus's today and found the addendum in those boxes.

It say's wire the 2K2 resistor between +12V & Bell trigger at the panel, so If I get chance tomorrow I'll call and try it.

I'll update this thread with the result.

 

Internal sounders can act up when connected in parallel with the db, resistor is meant to eliminate the feedback from db that causes this.

Can you program another output on the panel and connect the sb to this

The 9448+ is limited on outputs, and as OXO has said, the output pin does not supply enough current for a soundbomb, but if the resistor doesn't do the trick, then I'll follow OXO & stick a relay in the panel across the +12V & Bell trigger.