Missing derivative part in the PID module?

lneuhaus / pyrpl

pyrpl turns your RedPitaya into a powerful DSP device, especially suitable as a lockbox in quantum optics experiments.

http://lneuhaus.github.io/pyrpl/

MIT License

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Missing derivative part in the PID module? #421

Open mmaeusezahl opened 3 years ago

mmaeusezahl commented 3 years ago

I noticed that there is currently no D-part availble (it is even disabled in the FPGA design) in the PID controller. Is there any particular reason for this? I could find the commit in which this was introduced (https://github.com/lneuhaus/pyrpl/commit/82281094caf0409c24494e9bc3cf5bf10535eda5) but not any specific information in the commit message.

Thanks for the nice project and any useful hint!

GuanhaoHuang commented 2 years ago

I am also having the same problem trying to use a differentiator in the board, but not able to do so. I tried to bring back the codes that was commented out but it seems that those were commented out a long time ago and the gain register doesn't allow me to set at correct frequency and instead assigned something like 1e-4Hz. Is there any reason the derivative was taken down?

GuanhaoHuang commented 2 years ago

Ah it really looks like it's disabled on the hardware level. Even though everything in the pid class seems to work fine but the derivative doesn't do anything.