Oct.9, 2008
SelisÖnelİ
40
Tank level problem:
Feedback control Scenario 1
nFeedback control schematic (Simplified Block diagram):
nShows each signal and device (process)
nBlocks represent dynamic elements
nF1 is manipulated and F2 is the disturbance
nControl valve à Fail-close (air-to-open) to prevent tank overflow on loss of instrument air or valve failure
n
F1
F2
h
hm
hsp
Pv
Controller
Valve
Process
Level
Transmitter