ABB ACS880-x04, Firmware Manual

Page: 318 / 604

318 Parameters
40.33 Set 1 integration
time Defines the integration time for the process PID controller.
This time needs to be set to the same order of magnitude as
the reaction time of the process being controlled, otherwise
instability will result.
Note: Setting this value to 0 disables the “I” part, turning the
PID controller into a PD controller.
60.0 s
0.0 … 32767.0 s Integration time. 1 = 1 s
40.34 Set 1 derivation
time Defines the derivation time of the process PID controller. The
derivative component at the controller output is calculated on
basis of two consecutive error values (E
K-1
and E
K
) according
to the following formula:
PID DERIV TIME × (E
K
- E
K-1
)/ T
S
, in which
T
S
= 2 ms sample time
E = Error = Process reference - process feedback.
0.000 s
0.000 … 10.000 s Derivation time. 1000 = 1 s
40.35 Set 1 derivation
filter time Defines the time constant of the 1-pole filter used to smooth
the derivative component of the process PID controller. 0.0 s
0.0 … 10.0 s Filter time constant. 10 = 1 s
No. Name/Value Description Def / FbEq16
Ti
O
I
G × I
G × I
I = controller input (error)
O = controller output
G = gain
Ti = integration time
Time
Error/Controller output
63
%
100
T
t
O = I × (1 - e
-t /T
)
I = filter input (step)
O = filter output
t = time
T = filter time constant
Unfiltered signal
Filtered signal