Riipple test with 6254a

[Rafi2003]

Hi

I'm an experience user of CVI but newbie in DAQ application.

The task I'm facing now is to measure ripple on power supply line.

The MIO card available is 6254a.

1) Any recommendation how to start?, relevant examples? etc...

2) Is it possible to run simulations (using the DAQmx) without the MIO card plugged in my PC?

3) I don't mind to use LabVew if it make the job easier...

Thanks

Rafi

[Kenn_N]

Thanks for contacting National Instruments

Your application sounds like a straight forward analog acquistion.  I will address each of your questions.

1) Any recommendation how to start?, relevant examples? etc...
      
       There are examples in your CVI directory, as well as the NI Example Finder.  The Example Finder (Help >> Find Examples) contains many examples for LabVIEW to accomplish DAQ tasks.  The CVI directory on your PC located at C:\Program Files\National Instruments\CVI80\samples\DAQmx\Analog In\Measure Voltage.  This directory may vary depending on the CVI version.

2) Is it possible to run simulations (using the DAQmx) without the MIO card plugged in my PC?

        First see this link.  What are NI-DAQmx Simulated Devices and How Do I Use Them?  This should get you started in simulating the board to do testing.

3) I don't mind to use LabVew if it make the job easier...

       LabVIEW has many existing examples that will probably do something very close to what you may need, but if you are more comfortable in CVI there isn't a compelling reason to use LV other than you may find more examples and tutorials than CVI in regards to DAQ applications.

If you are in need of further assistance let us know and be sure to search the online knowledge base articles and previous discussion forum posts, thanks.

Kenn N.
National Instruments
Applications Engineer.

[Rafi2003]

Hi Kenn

Thanks for your help.

I was able to simulate the MIO6254 and experiment with it.  Then, I loaded a Voltage input channel called "Get analog Voltage.vi" which I found in some application.  ( I don't know whether it is a NI sample or some application built around an NI sample...).

The physical input is connected to Dev1/ai0 which is my simulated 6254.  The vi measure mean voltage (I always get 0) and vpp (I get 20.9....I can't tell if it's volts or mv or uv)

Questions:

1) Does the simulated device has a signal generator in it? or do I reas some simulated noise?

2) Where do I find the units of the measurement?

3) To continue with my experimentation, I would like to connect a signal generator to this vi.  Can you guid me how to do it?  Do I need a simulated Signal Generator instrument, or, may I use a signal generator function?

Thanks in advance

Rafi

[Kenn_N]

Rafi,

Good to hear you got your simulated devices working.

If you go to the test panels in MAX for your simulated device you can run the simulation and you see a sine wave generated that oscilates full scale of the range you specify. This is why you get a mean of 0. That is all you can do in terms of simulation.  If you want to get a more dynamic signal on the ai channel you have to actually install the card and input a waveform. 

There are sine wave functions in CVI as well as other generator functions, but you can't connect them to a device input.  You can connect them to a device output, and monitor what you are sending to the output and route it into the input, but again you need the card inserted.

The units of your measurement should be specified in the range you have set for your task.

Regards