GE AF-650 GP Design And Installation Manual page 66

Application Set-Up Examples
Parameter
Parameter PI-00 Speed PID
Feedback Source
Parameter PI-02 Speed PID Propor-
tional Gain
Parameter PI-03 Speed PID Integral
Time
Parameter PI-04 Speed PID Differ-
entiation Time
Parameter PI-05 Speed PID Diff.
Gain Limit
Parameter PI-06 Speed PID
Lowpass Filter Time
Table 6.16 Speed Control Parameters
In Table 6.17 it is assumed that all other parameters and switches remain at their default setting.
Function
1) Make sure that the motor runs properly. Do the following:
Set the motor parameters using nameplate data
Have the frequency converter makes an auto tune
2) Check the motor is running and the encoder is attached properly. Do the following:
Press the "Hand" keypad key. Check that the motor is
running and note in which direction it is turning
(henceforth referred to as the "positive direction").
Go to parameter DR-20 Motor Angle. Turn the motor
slowly in the positive direction. It must be turned so
slowly (only a few RPM) that it can be determined if the
value in parameter DR-20 Motor Angle is increasing or
decreasing.
If parameter DR-20 Motor Angle is decreasing then
change the encoder direction in parameter E-81 Term
32/33 Encoder Direction.
3) Make sure that the drive limits are set to safe values
Set acceptable limits for the references.
MG35M402
AF-650 GP™ Design and Installation Guide
Description of function
Select from which input the Speed PID should get its feedback.
The higher the value - the quicker the control. However, too high value may lead to oscillations.
Eliminates steady state speed error. Lower value means quick reaction. However, too low value may
lead to oscillations.
Provides a gain proportional to the rate of change of the feedback. A setting of zero disables the
differentiator.
If there are quick changes in reference or feedback in a given application - which means that the error
changes swiftly - the differentiator may soon become too dominant. This is because it reacts to
changes in the error. The quicker the error changes, the stronger the differentiator gain is. The differen-
tiator gain can thus be limited to allow setting of the reasonable differentiation time for slow changes
and a suitably quick gain for quick changes.
A low-pass filter that dampens oscillations on the feedback signal and improves steady state
performance. However, too large filter time deteriorates the dynamic performance of the Speed PID
control.
Practical settings of parameter PI-06 taken from the number of pulses per revolution on from encoder
(PPR):
Encoder PPR Parameter PI-06 Speed PID Lowpass
Filter Time
512 10 ms
1024 5 ms
2048 2 ms
4096 1 ms
Parameter
P-02 to P-07
F-04 & F-05
Parameter P-04 Aut
o Tune
Parameter DR-20 M
otor Angle
Parameter E-81 Ter
m 32/33 Encoder
Direction
Parameter F-52 Mini
mum Reference
parameter F-53 Ma
ximum Reference
DET-767c All rights reserved.
Setting
As specified by motor nameplate
[1] Enable complete auto tune
Set a positive reference.
N.A. (read-only parameter) Note: An increasing value
overflows at 65535 and starts again at 0.
[1] Counter clockwise (if parameter DR-20 Motor Angle is
decreasing)
0 RPM
1500 RPM
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