90 ACH550-UH User’s Manual
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Group 23: Speed Control
This group defines variables used for speed control operation.
Group 23: Speed Control
Code Description Range Resolution Default S
2301 PROP GAIN 0.00…200.00 0.01 3.00
Sets the relative gain for the speed controller.
• Larger values may cause speed oscillation.
• The figure shows the speed controller output
after an error step (error remains constant).
Note! You can use parameter 2305, AUTOTUNE
RUN, to automatically set proportional gain.
2302 INTEGRATION TIME 0.00…600.00 s 0.01 s 2.50
Sets the integration time for the speed
controller.
• The integration time defines the rate at
which the controller output changes for a
constant error value.
• Shorter integration times correct continuous
errors faster.
• Control becomes unstable if the integration
time is too short.
• The figure shows the speed controller
output after an error step (error remains
constant).
Note! You can use parameter 2305,
AUTOTUNE RUN, to automatically set
proportional gain.
2303 DERIVATION TIME 0…10000 ms 1 ms 0
Sets the derivation time for the speed controller.
• Derivative action makes the control more
responsive to error value changes.
• The longer the derivation time, the more the
speed controller output is boosted during the
change.
• If the derivation time is set to zero, the
controller works as a PI controller, otherwise as
a PID controller.
The figure shows the speed controller output
after an error step when the error remains
constant.
Gain = K
p
= 1
T
I
= Integration time = 0
T
D
= Derivation time = 0
Controller
Error Value
Controller Output
t
%
e = Error value
output =
K
p
*
e
T
I
Controller Output
t
%
Gain = K
p
= 1
T
I
= Integration time > 0
T
D
= Derivation time = 0
K
p
*
e
e = Error value
K
p
*
e
Gain = K
p
= 1
T
I
= Integration time > 0
T
D
= Derivation time > 0
T
s
= Sample time period = 2 ms
∆e = Error value change between two samples
T
I
K
p
*
e
Error Value
Controller Output
t
%
e = Error value
K
p
*
T
D
*
∆
e
T
s
K
p
*
e
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