The type of the source is cluster of 3 elements. The type of the sink is 1D array of waveform. The cluster to array conversion is NOT work, any document to discuss this or any hints? Thanks.
Data types have to match to use the function. In your case, the cluster would have to contain waveform data types. Instead of trying to wire the output of the function to your 1D array, right click on the output and select Create Indicator. You should be able to tell the difference between this indicator and the array of waveforms. If you can't tell the difference, post the code so someone can look at it.