Save the power spectrum waveform

[joaomatos]

Hey labview masters, I need help! I am developing a labview program to calculate the power spectrum of a waveform injected in a 4461 signal acquisition interface. The program obtains the fft of the captured signal and return the power spectrum chart, as well as the noise floor. It is then sent to the host via TCP connection.

Everything is functioning properly except I cant save the power spectrum signal to further sent it to the host. I tried plotting all x/y values via the plot waveform.vi command, except I cant add labels to the axis.

Can you tell me how to plot the complete power spectrum chart, add labels and save it in the pc?

Thank you guys

João Matos

[RTSLVU]

I don't have any DAQ hardware so I can't run your program but...

Here is how I have saved graphs to my computer for printing later. 

Get your graph looking the way you want then export an image to a file using a property node

[joaomatos]

The problem is that I can't convert my power spectrum to an image, how do I do it?

I tried converting it to a XY plot, but then I cant add labels.

[RTSLVU]

Isn't your power spectrum displayed in the Waveform Chart?

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@joaomatos wrote:

The problem is that I can't convert my power spectrum to an image, how do I do it?

I tried converting it to a XY plot, but then I cant add labels.

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[johnsold · Accepted solution]

Export image is an Invoke node, not a property node.

Right click on the Waveform Chart terminal and select Create >> Invoke Node >> Export Image.

Lynn

[joaomatos]

Thank you my friend, that is the better solution!

How can I get the image and then sent it via TCP IP?

[RTSLVU]

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@joaomatos wrote:

Thank you my friend, that is the better solution!

How can I get the image and then sent it via TCP IP?

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Send it to what?

How about using the email vi's to attach the image and email it? 

[joaomatos]

I need to send the image via TCP IP to a python interface that is waiting to receive data via a TCP socket.

How can I convert it to a bit stream?

[johnsold]

Use Picture to Pixmap.vi from the Graphics & Sound >> Picture Functions palette.  Then extract the image array from the image data cluster. It is  an array of bytes which you should be able to use. Read the Detailed Help for the VI to get more information about the format.

Lynn 

[joaomatos]

I am not being able to send the image in correct format. I use the invoke node -> get image from the waveform chart which converts it to image data.

How can I convert the image data to string and send it via TCP to the pyhton interface, so that I can reconstruct it on the other side.

JM