Re: Cylinder temp monitoring - Idratek

[Kevin Hawkins <yahoogroupskh@xxxxxxxxxxxxxx>]

Alex - sorry ..the question you really asked is about temperature to
voltage conversion.  I had a quick look on Google for a low cost module
, but only found a variety of IC's that perform the function.  I'm sure
there must be built up modules somewhere.

However it would be better to use one of the temperature sensors that
outputs via a 20ma current loop.  If you place a resistor in that loop
then the voltage across it, measured using the QAI-002, would be
proportional to the temperature.   20ma loops are widely used for low
voltage sensing as they reduce inaccuracies due to wire length and
induced electrical noise.

There are many such sensors available - a quick look on eBay for
temperature + 20ma will pull some up although they are from China...   .

http://www.ebay.co.uk/itm/300832680770

You should select a sensor that as closely as possible matches the range
you wish to measure.  The above is quite well suited measuring 0-100 C
over 4-20ma.  You would then calculate the resistor value to give you a
voltage drop close to the maximum the QAI-002 can measure based on the
20ma max current.

K

On 01/02/2013 23:26, Kevin Hawkins wrote:
> I do monitor mine but it's probably not an easy solution for you to
> replicate.  I have1-wire temp sensors attached to an OPNone which
> outputs xAP messages - and of course Cortex recognise these as it has
> inbuilt xAP support.   The HAH LiveBox could also do this or the TOM10
> with the a PC based xAP application.  I think there's also a xAP PC
> application that uses the Dallas USB adaptor.
>
> I understand your difficulty with using one of the standard IDRATek
> modules but it might be possible by extending the  module sensor with
a
> short wire length ?  Karam would be able to advise or maybe even
provide
> a special module with the sensor on a flying lead.
>
>       K
>
> On 01/02/2013 23:01, alex007c@xxxxxxx wrote:
>> Has anyone found a way of measuring temperature using an analogue
Idratek module?  I'm hoping there's a way of measuring the temperature in
two locations on my hot water cylinder.  Anyone done this?
>>
>> http://www.idratek.com/products/catalogue/qai-002/
>>
>> Alex
>>
>> [Non-text portions of this message have been removed]
>>
>>
>>
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