Different Outputs With Sine and High Throughput Sine & Cosine Functions

Issue Details

When I test my VI, I see a large difference between the standard Sine.vi and the High Throughput Sine and Cosine.vi. For example, with an input of 0.1 radians, Sine.vi returns the correct value of 0.0998395, while the FPGA version outputs 0.309035. I’d like to understand where this difference comes from and whether there’s any setup or configuration I’m missing.

Solution

Both functions output the correct value. The difference between them is that the Sine function accepts input in radians, while the input to the High Throughput Sine & Cosine function must be in units of pi radians, which use fewer FPGA resources than radians. If you have a value in radians, divide that value by pi before wiring the value to this input terminal. You can see an example of this implementation below:

Note: This image is a LabVIEW snippet, which includes LabVIEW code that you can reuse in your project. To use a snippet, right-click the image, save it to your computer, and drag the file onto your LabVIEW diagram.