. superposition.of.p,.i.and.d.portions, Superposition of p, i and d portions – Burkert Type 8693 User Manual

Page 237

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237

General Rules (Appendix)

57.4. superposition of p, i and d portions

Function:

+

+

=

(7)

t

d

d

X

d

d

K

t

d

d

X

i

T

1

d

X

p

K

Y

Where Kp · Ti = Tn and Kd/Kp = Tv the function of the pid controller is calculated according to the following
equation:

+

+

=

(8)

)

t

d

d

X

d

v

T

t

d

d

X

n

T

1

d

X

(

p

K

Y

Kp Proportional coefficient / amplification factor

Tn Reset time

(Time which is required to obtain an equally large change in the actuating variable by the I portion as
occurs with 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

Step response of the PID controller

Ramp response of the PID controller

Xd

X

D-portion

X

Y

I-portion

P-portion

I-portion

P-portion

D-portion

Y

Reset time Tn

Hold-back time Tv

Kp⋅Xd

t

t

t

t

Figure 136: Characteristic of step response and ramp response of PID controller

english

Type 8692,8693

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