Superposition.of.p,.I.and.d.portions - EBRO ARMATUREN EP 501 C Operating Instructions Manual

35.4. Superposition of P, I and D Portions
Function:
= ⋅ +
Y K p X d
i T
Where Kp · Ti = Tn and Kd/Kp = Tv the function of the PID controller is calculated according to the following
equation:
= ⋅ +
Y K p ( X d
Kp Proportional coefficient / proportional gain
Tn Reset time
(Time which is required to obtain an equally large change in the actuating variable by the I portion, as
occurs due to the P portion)
Tv Derivative time
(Time by which a certain actuating variable is reached earlier on account of the D portion than with a
pure P-controller)
Step.response.and.ramp.response.of.the.PID.controller
X
Xd
Y
D-portion
Kp⋅Xd
Step response of the PID controller
Figure 114: Characteristic of step response and ramp response of PID controller
196
1 d X d
∫
+
X d t d K d
t d
1 d X d
∫
+
X d t d T v
T n t d
I-portion
P-portion
Reset time Tn
english
(7)
) (8)
X
t
Y
t
Ramp response of the PID controller
Typ EP 501
Additional technical information
Hold-back time Tv
t
I-portion
D-portion
P-portion
t