PD controller
— In the parameterization level, specify control parameters with
P
=
0.1
,
I
=
0
=
off
and
d
=
0
=
off
, and set derivative-action (rate) gain
dP
normally to a value between
5
and
10
.
— In the operating level, set the setpoint to the desired value and then modify the output vari-
able with using
cursor
keys (5) and such that the control valve slowly opens, and xd
becomes zero.
— Increase P value until control system inclines to oscillate.
— Set d value to 1s and then increase until oscillations cease.
— Increase P value until oscillations resume.
— Increase d value until no more oscillations can be determined.
— Proceed a few times in the same manner until oscillations cannot be suppressed any more.
Slightly decrease P value and d value so that the controlled system comes to abatement
again.
Correct offset by setting working point YP as indicated below:
In the steady-state of the plant, read the current value of output variable y and enter as
value for working point
YP
.
IMPORTANT:
Every change of setpoint also causes a change of working point
YP
.
PID controller
— In the parameterization level, specify control parameters with
P
=
0.1
,
I
=
2000
and
d
=
0
off
and set derivative-action (rate) gain
dP
to a value normally between
5
and
10
.
— In the operating level, set the setpoint to the desired value and then modify the controller out-
put value with the cursor keys (5) and such that the control valve slowly opens, and xd
becomes zero.
— Increase P value until the controlled system inclines to oscillate.
— Set d value to 1s and increase until oscillations cease.
— Slowly increase P value until oscillations resume.
— Increase d value until no more oscillations can be determined.
— Proceed a few times in the same manner until oscillations cannot be suppressed any more.
— Slightly decrease P and d value so that the controlled system comes to abatement again.
— Decrease I value until the plant inclines to oscillate again and increase again until oscilla-
tions cease.
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