As usual I'm learning plenty during the latest install, got a few questions on the tamper return for interest and doing it right.

What's the technical description for the tamper return on the G2? I'd like to connect a TR on an internal SAB (Elmdene) and it has a jumper setting to choose between "switched output" or "positive collector output".

Could anyone explain the difference between the two from an electronic POV?

Also, without giving details on the forum, as you know the resistance on the tamper return of the G2 (44) is "different" from the EOL resistances on the zones. What is the reason for this?

Thanks for educating me!

Its because its normally a switched neg input

I'm assuming by switched output that Elmdene mean open collector and the alternative being positive collector and that the jumper just connects in the resistor (not seen a datasheet or circuit- maybe someone else has). In electrical terms, one reason an open collector is used when the output signal level (sounder) may differ from that of the input (panel). The open collector allows the input equipment to pull the voltage up to the level required. Another reason is that the input circuit on the receiving circuit is an unknown and the pullup is an unknown. By combining pull-up resistors in parallel at each end, then the transistor may not be able to pull the voltage down when switched on. Finally, if the panel didn't have a pull up on the input signal, if the sounder was disconnected, then there would be no pull-up and the signal would float - which would not necessarily lead to a tamper condition.

In the Galaxy tamper signal case, the panel pulls up to 12V, so open collector should be fine. When not in tamper, the sounder will drive the pulled up (by the panel) tamper signal voltage down to 0V. (or in alarm terms - switched negative).

The difference with the tamper circuit and the EOL type zones is that EOL inputs are ADC (analog MUX prior to CPU I/O) and the tamper is digital (CPU I/O).

I've tried to explain simply, but may have made an a**e of that

And EOL zones need to be analog, because they need to band voltage ranges into input states (TAMPER O/C - MASKED - OPEN - CLOSED - TAMPER S/C).

Can't we give Driller 'Trade' membership, I'm sure he has earned it. Been a member for over five years now.

What do others think?

Can't we give Driller 'Trade' membership, I'm sure he has earned it. Been a member for over five years now.

What do others think?

He more than some trae members but thats hardly a pre qualifier.

If he is in the Fire and Security trade then I don't see why not.

Oh!

What do others think?

No, trade is trade.

Cleaning my own car does make me a "trade" valeter does it?

Ok, ok, ok

Thanks for the shout Magpye, really very kind of you and I would feel very privileged to be allowed onto the trade forums but I totally understand that this could be unacceptable to those in the trade here though. Still really appreciate the chance to have learned so much stuff on the public forums though and all the generous help I've received here over the years

Galaxy guy and james: been snowed under with work, will get back soon and look at your replies, thanks.

Edited October 15, 201213 yr by Driller