Re: Re: PIR's and HomeVision

[Kevin Hawkins <yahoogroupskh@xxxxxxxxxxxxxx>]

You will use the contacts in the PIR in a 'volts free' way - as per
Jons
post - do not bring the 12V back from the sensor into HV. These two
wires attached to the contacts can come back down the same CAT5 so you
will use 4 wires in all . There will be no connection between/across the
CAT5 individual wires at either end of the cable.  The power supply is
only there to power the electronics of the PIR's and will be totally
isolated from HV.  Reed contacts just the same - they are just connected
to the HV input 'volts free' ie just open circuit / shorted and should
not have 12V applied.

If you are series connecting the PIR's then you can use an additional
pair of wires for the other sensor contacts but the power wires will be
common. Also if you wish you could use two wires in parallel for the +
and two for the - to allow the cable to carry more current - but the
sensors do not draw much.

There is one slight risk you should be aware of and that is lightning.
It is possible that a storm could induce enough voltage in the CAT5 to
exceed the input port limitations on HV and this could damage the input
circuitry.  You can protect against this with opto isolators but it is
considerably more complex to wire up.   All the chips on HV are
socketed, very low cost and easily changeable and so most people just
live with this.

K


Bov wrote:
> Fantastic - I'll get 2 of those GJD PIRs, a 12v power supply and a
> bunch of Cat5 cables to plumb it into my HV unit.
>
> Presume I simply run a 12v circuit through each PIR and then back down
> the Cat5 to the HV?
>
> Can anyone tell me how I wire this up to the HV? I'm sure I can work
> it out with a bit of trial and error - just trying to save some time
:-)
>
> Also, with a reed switch - can I simply add that in the same way with
> a 12v circuit back to the HV unit?
>
> Cheers.
>
>
>
> --- In ukha_d@xxxxxxx, "Simon Coates" <simon@...>
wrote:
>
>> Bov,
>>
>> I use these
>>
>> http://www.gjd.co.uk/elite.htm
>>
>> Regards
>>
>> Simon
>>
>>   ----- Original Message -----
>>   From: Bov
>>   To: ukha_d@xxxxxxx
>>   Sent: 09 October 2008 20:57
>>   Subject: [ukha_d] PIR's and HomeVision
>>
>>
>>
>>   Can anyone help me with:
>>
>>   a) instructions for how to wire an infra red motion sensor to a
>>   standard homevision unit.
>>
>>   b) I presume it's the same for a reed switch?
>>
>>   c) recommend the right outdoors PIR motion sensor to use and
what
>>
> other
>
>>   kit I need for this.
>>
>>   Thanks.
>>
>>   Bov.
>>
>>
>>
>>
>>
>> [Non-text portions of this message have been removed]
>>
>>
>
>
>
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