Parameters: Controllers - Danfoss VLT AutomationDrive FC 300 Design Manual

FC 300 Design Guide

Parameters: Controllers

"
7-0* Speed PID Ctrl.
"
7-00 Speed PID Feedback Source
Option:
*
Motor feedb. P1-02
24V encoder
MCB 102
Function:
Selection of encoder for closed-loop feedback.
Par. 7-00 cannot be adjusted while the
motor is running.
7-02 Speed PID ProportionalGain
Range:
0.000 - 1.000
Function:
Indicates how many times to amplify the error
(deviation between the feedback signal and
the setpoint). It is used with Speed control,
closed loop, and Speed control, open loop
(par. 1-00). Quick control is obtained at high
amplification. If the amplification is too high,
the process may become unstable.
7-03 Speed PID Integral Time
Range:
2.0 - 20000.0 ms
Function:
Determines how long the internal PID controller
takes to correct the error. The greater the error,
the quicker the gain increases. The integral
time causes a delay of the signal and therefore
a dampening effect. It is used together with
Speed control, closed loop and Speed control,
open loop Flux control (par. 1-00).
Obtain quick control through a short integral time.
However, if this time is too short, the process
becomes unstable. If the integral time is long,
major deviations from the required reference may
occur, since the process regulator takes long to
regulate if an error has occurred.
7-04 Speed PID Differentiation Time
Range:
0.0 - 200.0 ms
* default setting ( )
How to Program
[0]
[1]
[2]
*
*
8.0ms
*
30.0ms
display text [ ] value for use in communication via serial communication port
MG.33.B3.22 - VLT is a registered Danfoss trademark
Function:
The differentiator does not react to a constant error.
It only provides a gain if the error changes. The
quicker the error changes, the stronger the gain
from the differentiator. The gain is proportional
to the speed at which errors change. It is used
together with Speed control, closed loop (par. 1-00).
7-05 Speed PID Diff Gain Limit
Range:
1.000 - 20.000
Function:
It is possible to set a limit for the gain provided by
the differentiator. Since the D-gain increases at
higher frequencies, limiting the gain may be useful.
Thus you can obtain a pure D-link at low frequencies
0.015
and a constant D-link at higher frequencies. It is
used with Speed Control, Closed Loop (par. 1-00).
7-06 Speed PID Lowpass Filter Time
Range:
1.0 - 100.0 ms
Function:
The low-pass filter reduces the influence on control
and dampens oscillations on the feedback signal.
This is an advantage, e.g. if there is a great amount
of noise in the system. See illustration.
It is used with Speed control, closed loop and
Torque control, speed feedback (par. 1-00). If a
time constant (ô) e.g. of 100 ms is programmed,
the cut-off frequency for the low-pass filter will be
1/0.1= 10 RAD/sec., corresponding to (10/2 x p) =
1.6 Hz. The PID regulator only regulates a feedback
signal that varies by a frequency of less than 1.6 Hz.
If the feedback signal varies by a higher frequency
than 1.6 Hz, the PID regulator does not react.
*
5.000
*
10.0ms
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