VLT
®
8000 AQUA
Programming
NOTE
PID start frequency is always applied
in clockwise direction.
423 PID proportional gain
(PID PROP. GAIN)
Value:
0.00 - 10.00
✭
0.01
Function:
The proportional gain indicates the number of times
the deviation between the reference/setpoint and
the feedback signal is to be applied.
Used in
Closed loop
[1] (parameter 100).
Description of choice:
Quick regulation is obtained by a high gain, but if the
gain is too high, the process may become unstable.
424 PID integration time
(PID INTEGR.TIME)
Value:
0.01 - 9999.00 sec. (OFF)
✭
OFF
Function:
The integrator provides a constant change of the
output frequency during constant error between the
reference/setpoint and the feedback signal. The
greater the error, the quicker the integrator frequency
contribution will increase. The integration time is the
time needed by the integrator to reach the same gain
as the proportional gain for a given deviation.
Used in
Closed loop
[1] (parameter 100).
Description of choice:
Fast regulation is obtained in connection with a
short integration time. However, this time may be
too short, which means that the process may be
destabilised as a result of overswings.
If the integral time is long, major deviations
from the required set point may occur, since
the process regulator will take a long time to
regulate in relation to a given error.
425 PID differentiation time
(PID DIFF. TIME)
Value:
0.00 (OFF) - 10.00 sec.
✭
OFF
Function:
The differentiator does not react to a constant error. It
only contributes when the error changes. The quicker
the error changes, the stronger the contribution from
the differentiator will be. This influence is proportional
to the speed by which the deviation changes.
Used in
Closed loop
[1] (parameter 100).
Description of choice:
Fast regulation can be obtained by means of a
long differentiation time. However, this time may
be too long, which means that the process may
be destabilised as a result of overswings.
426 PID differentiator gain limit
(PID DIFF. GAIN)
Value:
5.0 - 50.0
✭
5.0
Function:
It is possible to set a limit for the differentiator gain.
The differentiator gain will increase if there are fast
changes, which is why it can be beneficial to limit
this gain, thereby obtaining a pure differentiator gain
at slow changes and a constant differentiator gain
where quick changes to the deviation are made.
Used in
Closed loop
[1] (parameter 100).
Description of choice:
Select a limit to differentiator gain as required.
427 PID lowpass filter time
(PID FILTER TIME)
Value:
0.01 - 10.00
✭
0.01
Function:
Oscillations on the feedback signal are dampened by
the lowpass filter in order to reduce their impact on
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.80.A7.22 - VLT is a registered Danfoss trademark
139
Rosewood STP ST42 General (Operation and Maintenance Manual - Part 4:
Section 6.3 Manufacturers Manuals 6.3.33 Danfoss VLT Aquadrive 8000) Vendor Manual
QP Id: VM207
Active: 03/09/2013
Page 145 of 208
