Array does Not resolve to a Fixed Size error

[euqinom2727]

Hey

I'm using the NI-9223 module. I want to be able to choose which inputs I want to acquire every time I run the VI. For that I used a lot of case structures, I tried on simulation and it functions. But when I tried to compile the code I got this error "Array Does Not Resolve to a Fixed Size".

I thought all of the arrays I used were with a fixed size, but now I'm not sure. Is this error occuring because for each case I have a different array wired to the output tunnel? 

And is this case structure the best solution to dinamically choose the inputs?

[crossrulz]

You have different lengths of arrays going to the same output tunnel in different cases.  For instance, case 0 has an empty array while case 1 has a 1 element array.  Since the maximum length in the cases is 4, you need to make all of the output arrays a length of 4.  To help your FIFOs, you can also output the number of elements that need to be sent (wire to the N on the FOR loop).

[euqinom2727]

What do you mean "to help your FIFOs"?

[ZYOng]

In my opinion, it is a waste of FPGA resources to have multiple relatively similar cases, with only one of them being active and the rest remaining idle most of the time.

I would program to write all 4 channels to the FIFO, then filter the data from selected channels on the host size.

[crossrulz · Accepted solution]

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@ZYOng wrote:

In my opinion, it is a waste of FPGA resources to have multiple relatively similar cases, with only one of them being active and the rest remaining idle most of the time.

I would program to write all 4 channels to the FIFO, then filter the data from selected channels on the host size.

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This is good advice.  The only difference I would do is wire up the N to the FOR loops that write to the FIFOs.  Doing this, the FPGA can limit what data goes up to the host.

[euqinom2727]

Thank you guys!