fpga wavefrom chart not working

[Eric416]

Compact rio using fpga. 9014/9114

In a fpga interface project if I create array and then connect it directly to a waveform chart it says the array needs to be of a fixed size.

However I have tested using a constant arrary of fixed size, initialise arrary to fixed size...etc but it always comes up with this error when trying to run the VI,

I have autopreallocate arrays and strings as indicated in the help file but still it comes up with the error.

Labview 11, sp1 (completely up to date)

I am running as "execute on development computer"

The arrary is of type fixed point 27bit integer(output from fft)

[Christian Mergl]

Did you really set the size by rightclick the array controls or contants as follows:

Also keep in mind that you should avoid to place large arrays at the fpga vis frontpanel since this takes up lots of fpga logic.

Christian

[Eric416]

yes I have set the size via that menu.

I am not worried about gate usage since it was supposed to be a "quick" diagnostic/test for  fpga FFT implementatgion I am working on.

I have worked around the issue by using DMA FIFO to send the data to the compact rio module and use that for displaying the outptut chart.

But it is inconvient not being able to chart it directly.

[Eric416]

[Christian Mergl · Accepted solution]

First of all, in your code you are using a Waveform Graph, not a Waveform Chart as what you wrote in your posts before!

Then DBL is currently a not supported datatype at the LV FPGA platform. There is also a strange issue with Graphs and Charts regarding their type propagation to the FXP datatype.

So the issue I found is that if you place a Waveform Graph or Chart from the palette, it's DBL. If you then connect a FXP Array you get the error you see since the Graph or Chart does not propagate to the FXP datatype. If you change the datatype of the Array to e.g. I32, the Graphs or Charts datatype changes to I32. If you change the I32 back to FXP then, everything works as it should.

This means for you, first create an I32 Array and connecti it to the Graph or Chart to get rid of the Fixed Size error. Then change the Array to FXP.

I need to do some more investigation regarding this issue and will post back.

Christian

[Eric416]

Yes that did work.

[Christian Mergl]

RnD reproduced the issue and filed CAR (Corrective Action Request) #357300. It will be fixed in one of the next versions of LabVIEW FPGA.

Christian