220 Parameters
Defines the derivation time of the speed controller. Derivative
action boosts the controller output if the 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 derivation makes the control more
responsive for disturbances. For simple applications,
derivative time is not normally required and should be left at
zero.
The speed error derivative must be filtered with a low pass
filter to eliminate disturbances.
The figure below shows the speed controller output after an
error step when the error remains constant.
0.000 s
0.000…10.000 s
Derivation time for speed controller.
1000 = 1 s
Defines the derivation filter time constant. See parameter
.
8 ms
0…10000 ms
Derivation filter time constant.
1 = 1 ms
No.
Name/Value
Description
Def/FbEq16
Gain = K
p
= 1
T
I
= Integration time > 0
T
D
= Derivation time > 0
T
s
= Sample time period = 250 µs
e = Error value change between two samples
K
p
×
T
D
×
e
T
s
Controller output
e = Error value
Error value
Time
T
I
K
p
× e
K
p
× e
%
ACS580 FW.book Page 220 Wednesday, September 21, 2016 9:48 PM