Intermittent faults - tampers in series

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As a Comfort installer for over ten years Household Automation has come across many poor Cytech installations.

Tamper in series

On a number of occasions we have been called out to Comfort installations to find that a number of sensors have had their tampers connected in series with each other and the case tamper and the bellbox. In principle there is nothing incorrect with this. However when you consider the last (problem) site we were called out to (installation by others than HA) it make sense not to wire the tampers in series but to wire them end of line resistor (EOL) as per comfort instructions (and indeed using the resistors that come with the main Comfort unit).

Consider the last installation the tamper route - 15 + PIR - each joined in the main CPU case, bell box, case tamper. 35+ connections over probably the best part of 1000m. The potential here for interference or poor connections is huge and unlike EOL method if there is a fault it will not be identified by the zone but simply by \"tamper\" - which could indicated a fault somewhere within the 35+ connections and 1000m of cable. Of course the potential for interference is also that much greater.

My advice - where ever possible wire zones as EOL. If you have an existing installation then get the cabling changed.

[strickers]

Hi,

Thanks for your advice. I have a SEM in my garage and all the 8 zones are taken up with various things including PIR\'s with integrated double EOL resistors. I only have 3 things I need to attach to the tamper connection on the SEM. 2 x bell boxes and the case switch. Both bell box’s only have a NC switch inside them (wired directly back to the panel) and I assume the tamper switch on the case in NC.
The question is, if I use terminal blocks to connect my devices then the comfort tamper connection will always see NC unless all 3 devices open. How do I go about connecting these correctly? I have tried to find this in manuals but all I can find is people saying connect them in series.. how do I do this?


Thanks,
Chris.

[ident]

The tampers should be connected in Series, never in Parallel
You can use external terminal blocks to connect series

You can also use spare zones programmed an 24 Hour N/C zone types for individual tampers