>can rewrite the PID equations into a FIR form, which opens up some interesting
>possibilities for say, a DSP approach or combining PID response with other
>filtering functions..

This sounds interesting. Can you supply a little more detail for one not too
familiar with FIR implemention (other than a maximal-length sequence
generator), and maybe a reference to a short FIR/IIR primer or article for
someone without the time to sink in deep DSP water?