Available in a git repository.
Repository: pypid
Browsable repository: pypid
Author: W. Trevor King

I've just finished rewriting my PID temperature control package in pure-Python, and it's now clean enough to go up on PyPI. Features:

• Backend-agnostic architecture. I've written a first-order process with dead time (FOPDT) test backend and a pymodbus-based backend for our Melcor MTCA controller, but it should be easy to plug in your own custom backend.
• The general PID controller will automatically tune your backend using any of a variety of tuning rules.

The README is posted on the PyPI page.