# Original Ziegler-Nichols gains listed after improved tuning rules are incorrect

From FBSwiki

Edition | Second |
---|---|

Version number | 3.0j |

Submission date | 31 Aug 2019 |

Your name | Richard Murray |

E-mail address | murray@cds.caltech.edu |

Chapter | 11 |

Page number | 11-13 |

Line number | 22, 23 |

Current status | Closed |

The gains listed in parenthesis in equation (11.10) are not quite correct:

- For the step response method in equation (11.10a) the original Ziegler-Nichols gains should be $k_p = 1.43T/(K \tau)$ and $k_i = 0.43 T / (K \tau^2)$.

- For the frequency response method in equation (11.10b) the original Ziegler-Nichols gains should be $k_p = 0.45 k_c$ and $k_i = 0.54 k_c/T_c$.