3.9 Parameters: 7-** Controllers
3.9.1 7-0* Speed PID Ctrl.
7-00 Speed PID Feedback Source
Option:
Function:
Select the encoder for closed loop
feedback.
The feedback may come from a
different encoder (typically mounted
on the application itself) than the
motor mounted encoder feedback
selected in
.
[0]
*
Motor feedb. P1-02
[1]
24V encoder
[2]
MCB 102
[3]
MCB 103
[4]
MCO Encoder 1 X56
[5]
MCO Encoder 2 X55
[6]
Analog input 53
[7]
Analog input 54
[8]
Frequency input 29
[9]
Frequency input 33
[11] MCB 15X
NOTE
This parameter cannot be adjusted while the motor is
running.
NOTE
If separate encoders are used (FC 302 only) the ramp
settings parameters in the following groups: 3-4*, 3-5*,
3-6*, 3-7* and 3-8* must be adjusted according to the gear
ratio between the two encoders.
7-02 Speed PID Proportional Gain
Range:
Function:
Size
related
*
[0.000 -
1.000 ]
Enter the speed controller proportional
gain. The proportional gain amplifies the
error (i.e. the deviation between the
feedback signal and the set-point). This
parameter is used with
[0] Speed open loop
and
[1] Speed
closed loop
control. Quick control is
obtained at high amplification. However if
the amplification is too great, the process
may become unstable.
Use this parameter for values with three
decimals. For a selection with four
decimals, use
.
7-03 Speed PID Integral Time
Range:
Function:
Size
related
*
[2.0 -
20000.0
ms]
Enter the speed controller integral time,
which determines the time the internal
PID control takes to correct errors. The
greater the error, the more quickly the
gain increases. The integral time causes a
delay of the signal and therefore a
dampening effect, and can be used to
eliminate steady state speed error. Obtain
quick control through a short integral
time, though if the integral time is too
short, the process becomes unstable. An
excessively long integral time disables the
integral action, leading to major deviations
from the required reference, since the
process regulator takes too long to
regulate errors. This parameter is used
with
[0] Speed open loop
and
[1] Speed
closed loop
control, set in
7-04 Speed PID Differentiation Time
Range:
Function:
Size
related
*
[0.0 -
200.0
ms]
Enter the speed controller differentiation
time. The differentiator does not react to
constant error. It provides gain propor-
tional to the rate of change of the speed
feedback. The quicker the error changes,
the stronger the gain from the differen-
tiator. The gain is proportional with the
speed at which errors change. Setting this
parameter to zero disables the differen-
tiator. This parameter is used with
[1] Speed closed
loop
control.
7-05 Speed PID Diff. Gain Limit
Range:
Function:
5.0
*
[1.0 -
20.0 ]
Set a limit for the gain provided by the differ-
entiator. Since the differential gain increases at
higher frequencies, limiting the gain may be
useful. For example, set up a pure D-link at
low frequencies and a constant D-link at
higher frequencies. This parameter is used
with
[1] Speed closed
loop
control.
7-06 Speed PID Lowpass Filter Time
Range:
Function:
Size
related
*
[1.0 -
100.0
ms]
Set a time constant for the speed control
low-pass filter. The low-pass filter improves
steady-state performance and dampens
oscillations on the feedback signal. This is an
advantage if there is a great amount on
noise in the system, see
. For
Parameter Descriptions
VLT
®
AutomationDrive Programmming Guide
MG33ME02 - VLT
®
is a registered Danfoss trademark
99
3
3