Multifunction DAQ

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Unsatisfied floating values

Hi everybody,

    I have some doubts on using DAQ usb 6211 the voltage reading in RSE mode which it was unsatisfiable i have created a program using daqmx functions and initialised with min val 0 and max val 10 and the given input config is RSE mode when i was i trying to read the values it reads the values in opposite side and sits at certain peak point at -10.62 i don't know how to config the min & max values and set it constant, if anybody knows give some idea to that and i have attached my simple vi with this.

 

Thanks in advance,

Regards,

Dinesh

 

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First thing: A quick look up in the 6211 spec will show that the unit supports +-10V range, but not a 0-10V range, so the DAQmx driver will choose that range.

Second: If you read the manual you migth have found that you need to provide a bias current path on your input. Yes, the input outputs a tiny current called bias current, and without a draining path this current loads the small input capacity and results in a voltage that increase (or decrease, depending on current sign) until it reaches the input limit... your -10.62V that matches quite well the max range from the spec of about +-10.4V. So my assumtion is that you have a floating or no source connected 🙂

 

RTFM help 😄 😄

Greetings from Germany
Henrik

LV since v3.1

“ground” is a convenient fantasy

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