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Ind. Eng. Chem. Res. 2011, 50, 1158
Volume 47, Issue 22 Synthesis of PID Tuning Rule Using the Desired ClosedLoop Response. Rames C. Panda* With reference to our paper entitled “Synthesis of PID Tuning rule Using the Desired Closed-Loop Response” the author’s request following corrections: Table 1, row 4, the PID controller parameters for IPDT type of process
GP(s) )
KPe-Ds τPs(as + 1)
will be
KC )
τP KP(τP + a + 2λ + D)
τI ) (τP + a + 2λ + D) +
D2(2λ + D) +β (τP + a + 2λ + D)
τD ) (τP + a)(2λ + D) +
(C2C0 - 0.5C3) C22 β(C0 + C2 /C1) + 2 + C1 KPC1 C1 KC
where C0 ) τP + a + 2λ + D;
C1 ) λ2 + 2λ + 0.5D; C2 ) 2 3 D2 2λ + D ; C3 ) D3 2λ + D 3 4
(
)
(
)
But as τD involves higher orders of time-delay terms, it may give high values of derivative gains especially for large (D/τP) processes. Hence, judicially, τD is found by equating coefficients of s terms of GC(s) with the same of the right-hand side of φ(s) where
φ(s) ) GC(s) )
τP(2λ + D)s2 + (τP + 2λ + D)s + 1 KP(λ + D)2
and thereby
τD )
IE1023782 10.1021/ie1023782 Published on Web 12/13/2010
τP(2λ + D) KP(λ + D)2
