CapnBry/HeaterMeter — pull request #9 by R-Burk (2014-10-16 01:34:51+00:00)
Title: [hm] Integrator / Derivative Changes

Integrator would stay stuck at a value even when the _pidOutput was
outside the 0-100 range.
Derivative was working against the instantaneous current temp. Put a
small filter so it's across the most recent 4 values. Using a second
derivative addition to bring it back close to real time. Also provides
extra steerage when the derivative is changing at a high rate