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PT100 Interface on myRIO

Hi,

 

I need to interface two PT100  on myRIO 1900 in order to acquire two tempeartures.

In order to minimize the error due to the cablelength I woul perform a 4 wire connection, to do this Ineed to use a bride, but I don't understan hoe to connect the bridge to teh Aor B connectors of myRIO.

 

can someone help me?

 

regards

David

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Message 1 of 6
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Have a look at the

MAX31865

 

I think the myRIO has no dedicated resistor measurement good enough for a Pt100

You get boards for about  5$

 

 

Greetings from Germany
Henrik

LV since v3.1

“ground” is a convenient fantasy

'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'


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Hi Henrik,

 

thanks for your suggestion, I need also to acquire 2 resistance values(not RTD) but I need an extreme accuracy of measurements, so I would like to implement a 4 wire measurements do you have an idea about which one can be the best solution?

 

ciao

david

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@David15 wrote:
.. I need an extreme accuracy of measurements...

And what do you mean with 'extreme accuracy' ??

 

A colleague just go with a good ol' ASL F900  ... 😄

 

Spoiler
and that's only half the battle
(or a quarter??)
a good known(!) reference resistor,
a good known(!) SPRT 
some ITS90 reference points (at least a triple point water cell)
Greetings from Germany
Henrik

LV since v3.1

“ground” is a convenient fantasy

'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'


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Message 4 of 6
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I

need to read milli ohm.

 

ciao

David

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Message 5 of 6
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Oh, come on, what does it mean 'need to read milli ohm' ???

Please learn how to write and read metrological requirements 😉

 

 

If you need mOhm accuracy reading a 100 Ohm resistor (or Pt100) that is 10ppm .

Usually a job for a 8.5 digit meter and not a myRio 😄  see here

The trick is to use comparison techniques ...  like a bridge

 

Greetings from Germany
Henrik

LV since v3.1

“ground” is a convenient fantasy

'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'


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