Chris Hardy, Cross Company Integrated Systems Group
Cycling motors on and off could be a way to meet demand; minimize starts, stops, and run time; and equalize run time between motors using a scheme.
How can a system control multiple process variables with only one output? A system can limit both values simultaneously. The operator enters setpoints for both and both act as limits.
Some PID loops cannot be satisfactorily tuned by adjusting the three primary constants. When combined with good basic tuning, advanced methods can improve stability, responsiveness, and limit overshooting.