This application note describes the conversion from the continuous to the discrete time domain, which is essential for every implementation on a digital processor. A routine is then presented that implements the discrete time representation of the PI controller.
The document explains how to convert a Proportional-Integral (PI) controller from the continuous time domain to the discrete time domain for use with digital processors. It details two approximation methods: Zero Order Hold (ZOH) and First Order Hold (FOH), providing the corresponding difference equations required for implementation.
All coefficients and signals must be scaled to the common 1.15 fixed-point representation.
Wind-up is avoided by saturating the current sum whenever it exceeds +1 or is less than -1.