| for a proportional plus derivative element with an additional first-order lag the ratio of the maximum gain resulting from the proportional plus derivative action with first-order lag to the gain resulting from proportional action only |
SEE: Figure 18.
Note 1 to entry: The transfer function of a PD element with first-order lag is
and using the derivative action gain a = Td/T1 the transfer function may be written
|KP||is the proportional action coefficient;|
|Td||is the rate time;|
|T1||is the time constant;|
|a||is the derivative action gain, 1 < a < ∞;|
|s||is the complex variable of the Laplace transform;|
|U(s)||is the input transform;|
|V(s)||is the output transform.|
Note 2 to entry: This entry was numbered 351-28-29 in IEC 60050-351:2006.