problem with daqcard700

[Lauranne]

Hello, 

I have a daqcard 700 and installed the driver NI 6.9.3 (the last recommanded for this card). I use a 50 pin cable as prescribed.

It's not possible to obtain a stable signal. I tried all of the pin but nothing. There is something like noise; vrey amplified noise. I know that the signal at the entry of the cable is right.

Have you any idea about the cause of my problem ?

Thank you very much for your help !!

Lauranne 

[The_Red_Barron]

Howdy Lauranne!

 What is the source of the signal you are measuring and how have you verified that the signal is correct at the cable entry point?  Does the noise you are seeing look like white noise or does it center around a specific frequency, perhaps 60Hz?  Also, what type of measurement (RSE or Differential) are you using and what interface are you using to read the values (LabVIEW program, test panels, etc...)?

 The Field Wiring and Noise Considerations for Analog Signals tutorial has a lot of useful information about how to connect your signals to prevent interference.  I would recommend reading it over to help troubleshoot the source of your issue.

Regards,

[Lauranne]

hello

Thanks for your answer. But it was not the solution.

Actually, it was not "noise" but a problem with my ground : I wanted to measure a force with a sensor through an amplificator. This ground is different of the ground of my laptop. The only way to don't habe perturbation is to use my laptop on battery !

Now, I found an other solution : put a cable between the laptop loader and the ground of the amplificator. 

Regards,

Lauranne