ABB ACH550-UH User Manual page 126

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Group 23: SPEED CONTROL
This group defines variables used for speed control operation.
Code Description
2301 PROP GAIN
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
to automatically set the proportional
RUN
gain.
2302 INTEGRATION TIME
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
to automatically set the integration time.
RUN
2303 DERIVATION TIME
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 below shows the speed controller output after an error step when the error remains constant.
Gain = K = 1
p
= Integration time > 0
T
I
= Derivation time > 0
T
D
= Sample time period = 2 ms
T
s
e = Error value change between two samples
Parameters
Group 23: Speed Control
Range
0.00...200.00
%
AUTOTUNE
Controller
output =
K · e
p
0.00...600.00 s
%
K · e
p
K · e
p
AUTOTUNE
0...10000 ms
%
e
K · T ·
p D
T
K · e
s
p
K · e
p
ACH550-UH User's Manual
Resolution Default
0.01 3.00
Gain = K
T
T
Error value
Controller output
0.01 s 0.50 s
Controller output
Gain = K
T
T
T
I
1 ms 0 ms
T
I
S
= 1
p
= Integration time = 0
I
= Derivation time = 0
D
e = Error value
t
= 1
p
= Integration time > 0
I
= Derivation time = 0
D
e = Error value
t
Controller output
Error value
e = Error value
t