However, modelers need an explanation of what the coefficients do from a more hydrological perspective, and possibly how the parameter values can be derived from more familiar/readily available information about real world hydrological control systems.
We have mathematical documentation of the PID control node here (the documentation is being refactored so this link could break soon):
https://deltares.github.io/Ribasim/core/equations.html#sec-PID
However, modelers need an explanation of what the coefficients do from a more hydrological perspective, and possibly how the parameter values can be derived from more familiar/readily available information about real world hydrological control systems.