NI-DAQ 6036E

[Minguccio]

I need help ASAP and would appreciate it very much if someone could help me out.

I need to develop a small application that needs to generate a sine wave and output it to a 6036E.

I am trying to use the express vi that generate a sine wave and feed it into the another express vi that outputs it to a 6036E.

The application is needed as a controller for a sensor. The scope of the project is to have an input voltage come in and compared to the sine wave generator and based on some criteria the sine wave generator will output a voltage so that it can control the sensor.

A reply or some sample vi would be greatly appreciated. I checked the sample vi within LabView and none conform to what I am looking for.

Thank you.

[devchander]

This Vi will do the job for you

It was taken form Examples shipped with labVIEW

You have also said  "I checked the sample vi within LabView and none conform to what I am looking for"

If this VI does not suit your purpose, plz elobrate further on your requirement

regards

Dev

Message Edited by devchander on 01-30-2006 11:34 PM

[Minguccio]

I build the executable and ran it on the laptop that will be used to control the device and I ran into a problem.

I received the following message:

"Onboard device memory underflow. Because of system and/or bus-bandwidth limitations, the driver could not write data to the device fast enough to keep up with the device output rate.

Reduce your sample rate, alter the data transfer method (from interrupts to DMA), use a product with more onboard memory, or reduce the number of programs your computer is executing concurrrently."

Any ideas on what can I change in the vi that you posted so that it would work?

My project involves in getting an input signal and then comparing it to the sine wave generator. The sine generator will manipulate the output signal in the case the input signal steps over a certain voltage.

Thank you.

[Minguccio]

This could also be due to the 6036E card having one channel dedicated to DMA.

I found on a different forum that I have to enable DMA for the device but I can't see how to do this using DAQmx.

Can someone please help, I need to get this application out the door by noon today.

Thank you.

[Minguccio]

Can I do a AO operation on a NI-PCI 4472? If so any ideas how?

Maybe I can overcome the buffer limitations by using the 4472 card.

Thank you.

[Tica]

Hi!

The PCI-4472 is an 8-channel dynamic signal acquisition device for making high-accuracy audio frequency measurements. It does not have any Analog Output channels.

If you need to generate an output signal at high speeds I recommend using any of our high-speed sources. You can find detailed information about them at our Products and Services website for Signal Generators.

Please let me know if you are interested in getting any of these devices.

Regards, 

Tica T

Applications Engineer

National Instruments

[devchander]

No you cannot do analog output generation on 4472.

It is an eight channel Analog Input  DSA card

[Minguccio]

I have tryed the vi but I had to change a few things. Please see attached vi for the changes I have made to take care of buffer underflow problems.

The only problem now is that when I measure the signal with an oscilloscope I cannot get a pure sinusoidal wave. The signal starts to look like a square wave. I need to bring the signal up to 20k.

Any suggestions would be greatly appreciated.

Thank you.

[Tom_W_[DE]]

Hi Minguccio-

In order to smooth your signal generation you should create more samples per cycle (using the Sampling Info parameters) and also increase your sampling/update rate.  What are you using for those parameters currently?

[Minguccio]

Tom,

the problem is that once I reach a certain sampling rate the vi crashes telling me that I have an underflow.
I tried other VIs but no luck.

I am to the point that the only conclusion I can draw from all of this is that the DAQ card cannot handle high frequencies.

Would you happen to know what is the maximum frequency that I can output on the 6036?

Thank you.