Testing program with DAQ assistant hardware

[Irene27]

Hi,

I am now testing my DAQ assistant with NI DAQ 9172 and input module is NI 9205.  All the signal type is voltage.  I used a power supply to input the signal.  The value shown on labVIEW indicator is changing although it can show the correct value for a few seconds.  These values change 0 to 10 volts until it reach correct value.  So, How can I make it to stable.   

And may I know is it the correct way that I use write LabVIEW measurement file.

This attachment is my example program.

regards,

[Robert_F]

Hello Irene,

How do you have the power supply connected to the NI-9205?  Do you have the positive terminal of the power supply connected to the four analog inputs as well as the negative terminal of the power supply connected to the common?  Without the common connected the analog measurements will not be able to accurately measure voltage.

You might want to make sure that the data is being acquired correctly in the test panel from Measurement & Automation Explorer (MAX).  You should read the same voltages in the test panel as in the DAQ Assistant setup window.  If you are not reading the correct voltage in the test panel, then you will not receive the correct voltage in you vi.

Normally when you set up your DAQ Assistant for continuous acquisition, your samples to read should be approximately 10% of your sampling rate. 

Here is a great example on how to use the DAQmx driver.