I'm working on controlling the flow of a pump. The pump in question has non-linear characteristic and I'm having trouble finding a transfer function so that I can tune the PID controller. Is such a non-linear system even possible to control with a PID-controller? I'm new to control systems and some help would be greatly appreciated.
The attached graphs show how the pump reacts when I make it go from 0-x % of the max flow. The x-axis displays time and the y-axis displays the signal from a flowmeter with a 4-20mA signal. Also please note that we can't read the Dead Time from the graphs since we didn't start the measuring exactly when we gave the pump a signal.
Last edited by Kelly Bramble; 03-25-2015 at 09:22 AM. Reason: Attach image directly to webpage