A tank level regulator control is shown in Figure AP4.1(a). It is desired to regulate the level h in response to a disturbance change q3. The block diagram shows small variable changes about the equilibrium conditions so that the desired hd(t) = 0. Determine the equation for the error E(s), and determine the steady-state error for a unit step disturbance when
(a) G(s) = K and
(b) G(s) = K/s.
Figure AP4.1
A tank level regulator.

Controller hl 7i Oritice Capacitance C Constant R Qls) Controller Hts) Hts) Desired height variation Es vartation