No output and input always set to high

[engineers]

Hi,
My DAQ all of the sudden does not seem to work properly.
There is no output that comes out. The voltage of the specified output line is always 0.
Also, the input lines voltage is always set to 1.
I wonder what happened?
Could you help me out identify the cause of that?

Thanks,

[Neil_S.]

engineers,

Thanks for posting to the NI forums.  What DAQ device are you using?  Are they digital or analog input and output lines?  Are you testing the device with Measurement and Automation test panels?  Did the device work correctly before?  Has anything changed since the device worked properly (i.e. the computer attached to the DAQ device, the software installed on the PC, the external wiring)  Let me know some of these additional details and I will be happy to see if we can figure out what is going on.

Regards,

Neil S.
Applications Engineer
National Instruments

[Labtrainer]

Hi,

I am hoping someone could give me a tip on how to set the right input voltage. I am using the NI 9211 and I‘ve used the custom scaling to convert voltage into pressure. The range of voltages i am getting is 28 to 70 mV. I’ve tried to set the right input range in the voltage input set up window, without success, I am still getting the error message 200077. I would appreciate if someone could give me a tip.

Thank

Glenn

[Neil_S.]

Labtrainer,

Thank you for posting to the NI Forums.  In the future I would recommend starting a new thread for a new issue.  This way each issue can get the attention that it deserves.  To answer your question, when you use a custom scale the range needs to be specified in terms of the scaled values rather than the unscaled values.  For example if you know the pressure will only vary between 10 psi and 50 psi you would select 10 and 50 as your lower and upper limits respectively.  You mention that the range of voltages varies from 28 mV to 70 mV, you should determine what pressures these values corrispond to.  Another approach would be to set the range to the maximum range of your sensor and then decrease the range until right before it begins to be clipped.

Let me know if you would like any further clarification.  If you have additional questions feel free to begin a new thread.

Good luck with your application.

Regards,

Neil S.
Applications Engineer
National Instruments

[Labtrainer]

Thank Neil S,

I have used the table instead of the linear equation as the scaling factor and I have entered the corresponding expected minimum and maximum pressures obtain from calibration into the custom scaling.

The pressure transducers that I am using are reading absolute pressure and I was wondering what would happen if the atmospheric pressure is even smaller than the one i.e. the one I’ve entered in the custom scaling as a minimum value on that particular day.

Thank

[Neil_S.]

Labtrainer,

If the pressure drops below the minimum value you specified the data will be clipped to your minimum value.  Therefore, I recommend the minimum value you specify is lower than any pressure you expect to receive.  The same applies to the upper limit you specify.  If the pressure ever exceeds this upper bound the data will be clipped to the maximum value you specified.

Let me know if you have any additional questions.

Regards,

Neil S.
Applications Engineer
National Instruments