USB 6211 problemas con múltiples entradas analógicas

[RULER46]

Foro de NI

            Antes que nada agradecerles, ya que este foro me ha sido de gran utilidad para mis proyectos, atreves de este foro pude sacar adelante muchas de los inconvenientes que se presentaban en mis VI´s.

            Esta ves mi problema es algo complejo y ya no se que puede ser el inconveniente, estoy trabajando con una placa adquisidora de datos USB 6211 uso 7 entradas analógicas de la “ai0” a al “ai6” las cuatro primeras tienen sensores de temperatura LM35 y las tres restantes cada una tiene un potenciómetro, el problema es que al variar el potenciómetro de la “ai6” me hace variar la entrada “ai0”, probé cada entrada individualmente y funcionan bien, fui agregando de a una hasta llegar a las 4 primeras (con los LM35) y funcionaba perfecto.

En otro VI probé del mismo modo las tres entradas restantes con potenciómetros, una a una hasta llegar a las tres y también funcionan bien.

            El problema me surge cuando uso todas las entradas (las 7 que mencione) o bien cuando tengo las entradas con sensor LM35 y al menos una con potenciómetro, esta ultima me afecta a alguna entrada de los LM35.

Por favor si alguien me puede dar una mano les estaré eternamente agradecido.

PD: Les envío la parte de adquisición de datos de mi VI que es donde tengo problemas.

[muks]

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Spanish to english

       First of all thank you, because this forum I have been very useful for my projects, this forum could dare take forward many of the difficulties that presented themselves in my VI's.

            This time my problem is complex and no longer can be the problem, I'm working with a motherboard 6211 USB data acquirers 7 analog inputs use the "AI0" to the "AI6" are the first four and LM35 temperature sensors the other three each have a potentiometer, the problem is that by varying the potentiometer "AI6" makes me change the entry "AI0" each entry individually tested and work well, I was adding one to reach the first 4 (with the LM35) and it worked perfect.

In another VI tried the same way the three remaining tickets potentiometers, one by one up to three and also work well.

            The problem arises when I use all the entries (the 7 mentioned), or when I have the LM35 sensor inputs and at least one potentiometer, the latter affects me some input of the LM35.

 

Please if anyone can give me a hand I will be forever grateful.

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Spanish board

[RULER46]

Alguna idea para mi problema??

            Espero haber sido claro con la explicación, cualquier duda me dicen y lo aclaramos pero necesito que alguien por favor me ayude con el tema por que no encuentro el inconveniente.

Gracias.

[James_W]

Es possible a pregunta en ingles? Alguna hay problema hablan en Espanol.

Los espanoles estas aqui:

http://forums.ni.com/ni/board?board.id=6170

Soy ingles lo siento por mi espanol.

James

[James_W]

1) Have you checked it is definitly not the H/W?

2) Can you post your DAQ code?

[RULER46]

Hi James, thanks for your reply.
I tested the 6211 USB Software "DAQ Diagnostic Utility 2.0" and did not find fault, it seems the problem is impedance DAQ entries.

http://digital.ni.com/public.nsf/allkb/EB8A69881276BD21862574030081A9C8 

http://digital.ni.com/public.nsf/allkb/EB8A69881276BD21862574030081A9C8

I will implement a voltage follower circuit or buffer and upon termination of the common tests results.
Thank you.
PS: I upload the code. 

[RULER46]

Gentlemen, sorry for the delay of the response.
Indeed, there was a problem of impedance, the solution that implements not to lower the frequency of sampling (the result is that too good), was to implement a voltage follower circuit to the inputs with an input potentiometers and add more grounded " AI7 "entry that is between the entry" AI0 "with LM35 and" AI6 "with potentiometer, the latter is the one that affected the first to LM35
I hope my problem is useful and my solution.
And sorry for my English

[RULER46]

Gentlemen, sorry for the delay of the response.
Indeed, there was a problem of impedance, the solution that implements not to lower the frequency of sampling (the result is that too good), was to implement a voltage follower circuit to the inputs with an input potentiometers and add more grounded " AI7 "entry that is between the entry" AI0 "with LM35 and" AI6 "with potentiometer, the latter is the one that affected the first to LM35
I hope my problem is useful and my solution.
And sorry for my English

[James_W]

Ruler46

No need to apologise for your English. It is VERY good, much better than my Spanish which I hardly ever use.

Hasta la vista!

James