APPENDIX
Supperposition of P-, I- and D components:
Y = Kp Xd +
Where Kp•Ti = Tn and
Y = Kp (Xd +
Kp :
Proportional action coefficient / gain
Tn :
Reset time (the time needed to achieve the same manipulated variable change by the I
component as is produced as the result of the P component).
Derivative action time (the time to achieve a specific manipulated variable on the basis of
Tv :
the D component earlier than when using a pure P controller).
X
Xd
Y
D component
Tn
Reset time
Step response of the PID controller
1
ƒ Xd dt + Kd
Ti
Kd
= Tv, results with regard to functioning of the PID controller:
Kp
1
ƒ Xd dt + Tv
Tn
t
}
I component
}
P component
t
E-41-
POSITIONER 1067
d Xd
dt
d Xd
)
dt
X
Y
Tv
Derivative action time
Rise response of the PID controller
t
}
I component
}
D component
}
P component
t