by Tony » Sat Apr 29, 2006 7:09 pm
Once you have the pressure sensor and the flow control valve, you will also need a PID controller to make it work.
PID stands for "proportional, integral, derivative". The idea is that the flow control valve must respond properly to detected pressure variations. How fast and how far it opens will determine if it will control at all, or become wildly unstable.
If it over corrects, it will probably flutter or oscillate. If it does not correct far enough, or fast enough it will not control pressure very well. The PID controller allows you to "tune" the response of the feedback system for optimum results.
See how it goes, but don't think for one moment that building a stable high performance closed loop pressure control system is going to be simple.
Also known as the infamous "Warpspeed" on some other Forums.