Azbil KFDB, User Manual

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Fig. 1-6. Controller Mechanism
(2) Integral Unit and Derivative Unit
The pressure of the feedback chamber of the proportional unit is fed to the integral (reset)
chamber of the proportional unit via the restriction and capacity chamber of the integral
unit in order to provide an integral (I) action. By adding the deriva tive unit, a derivative
(D) action can be attained.
A derivative bellows is provided in the chamber of the derivative unit and part of the
pneumatic output pressure is directly fed to this bellows to adjust the amplitude of
derivative action.
Fig. 1-7. Integral Unit and Derivative Unit