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Widely distributed temp sensors with limited power access.

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Widely distributed temp sensors with limited power access.

Postby robmur » Thu Aug 19, 2010 1:44 pm

Hi,
I'm looking to set up 6 temperature sensors, spread across a warehouse at varying heights and with very limited access to power connectors.

Cable run distance would be up to 90 meters, possibly further in future; so I guess that something like RS-422 converters and twisted pair cat 5e should allow a signal across such a distance. But was unsure about how your devices would receive power.

I was hopeful that you might be able to suggest a combination of your temp sensor + data logger + converter or whetever you think would be appropriate.

There's mention on the site that the sensors can work up to 400meters + up to 1K with the correct equipment, but I haven't yet found a technical page on the appropriate setup.

Kind regards,
robmur
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Re: Widely distributed temp sensors with limited power acces

Postby ziko » Fri Aug 20, 2010 9:39 am

Hi I would have a look at the enviromon system.

At the heart of the system is the EL005 logger, which has a micro controller and can store up to 250,000 samples. The EL005 uses a serial port to configure it on the computer and requires a 12V power supply which comes supplied with the unit. The logger is initially programmed on the PC and then can be left to run independent of the PC or remain connected to the PC. To view the data the logger would then be connected to the PC and it will then download the data when the software is running (software comes free).

http://www.picotech.com/e_loggers.html

To get your measurements from the sensors we have a range of sensors which can connect to the logger. These convert an analogue signal from a sensor or input into a digital reading which is stored by the logger. Up to 10 converters can be connected to one logger. We have a range of converters for different applications.

http://www.picotech.com/e_converters.html

I would recommend the EL001 converter which can take up to 3 temperature sensors (-30 to 70degC)

http://www.picotech.com/e_converters.html#el001

You can have a look at the temperature starter kit, which comes with an EL005 and EL001 and 3 EL015 temperature sensors. All you would then need to do is get another EL001 and three EL015s.

http://www.picotech.com/e_starter_kits.html

In terms of distance using the normal cable the maximum distance between a converter would be 400meters, you can get longer distances if you use something like a CAT6 twisted and shielded cable.

Hope this helps.

Kind regards
Ziko

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Re: Widely distributed temp sensors with limited power acces

Postby robmur » Fri Aug 20, 2010 5:50 pm

Thanks,
looks like I'd need 6 EL001s with one EL015 sensor each, due to the distance between sensors (1 sensor on an associated warehouse rack).

I'd be hoping to get a star type layout, with each sensor's cable running back close to the logger.

I've been looking at
http://www.picotech.com/document/pdf/emw.en-9.pdf
and the fixed network layout suggested on pages 49-51.

The diagram of the EL009 wall socket pin layout suggests that the EL001s can be wired in parallel, rather than the serial daisy chain as shown in the adjacent diagram. Would that be correct?

I.E.
1 EL005 with 6 EL009 ports close by. Each EL009 is connected to an EL001 at a range of 10 meters to 90 meters. One EL015 connects to each EL001.
And the EL001s are smart enough to avoid talking over each other?

Alternatively, what's the limit on how far the sensor can be reliably run from the EL001? 5m I presume.
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Re: Widely distributed temp sensors with limited power acces

Postby ziko » Mon Aug 23, 2010 8:24 am

Hi,

Its still a daisy chain. Each converter and logger have two network connectors, so you can have 2 strains of converters coming from the logger, this can be 2 separate strands or a loop where you connect strands together.

Kind regards
Ziko

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