i’m writing a current (id = 1) and voltage (id = 2) signal to a .jls file… when i launch the joulescope reader on this file, i want to see the (computed???) p signal; instead i just see a blank slate…
what steps am i missing???
You have to write the power signal. signal_id doesn’t matter, but you can use id=3.
The JLS file format does not compute power by multiplying current and voltage together.
This choice is intentional. JLS files are designed to support huge amounts of data, and they are highly optimized to deliver data quickly. They do this use a “fractal” style method of storing zoomed out views of the data. When you open a 10 TB JLS file, it uses the zoomed out views to quickly display the data without having to process all 10 TB. Computing power by multiplying together the zoomed out data is NOT the same as computing power by multiplying sample-by-sample.
Joulescopes multiply current and voltage sample-by-sample, then downsample as desired and store to JLS.