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Parameter Descriptions
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
1-02 Flux Motor Feedback Source.
This parameter cannot be adjusted
while the motor is running.
[0]
Motor feedb. P1-02
*
[1]
24V encoder
[2]
MCB 102
[3]
MCB 103
[5]
MCO Encoder 2
[6]
Analog input 53
[7]
Analog input 54
[8]
Frequency input 29
[9]
Frequency input 33
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:
Application
[0.000 -
Enter the speed controller proportional
dependent
1.000 ]
gain. The proportional gain amplifies
*
the error (i.e., the deviation between the
feedback signal and the setpoint). This
parameter is used with 1-00 Configu-
ration Mode Speed open-loop [0] and
Speed closed-loop [1] control. Quick
control is obtained at high amplifi-
cation. 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 3-83 Quick Stop S-ramp
Ratio at Decel. Start.
FC 300 Programming Guide
Application
dependent
Application
dependent
5.0
®
MG.33.MA.22 - VLT
is a registered Danfoss trademark
7-03 Speed PID Integral Time
Range:
Function:
[2.0 -
Enter the speed controller integral time,
20000.0
which determines the time the internal
*
ms]
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
damping 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
Speed open-loop [0] and Speed closed-
loop [1] control, set in 1-00 Configuration
Mode.
7-04 Speed PID Differentiation Time
Range:
Function:
[0.0 -
Enter the speed controller differen-
200.0
tiation time. The differentiator does not
*
ms]
react to constant error. It provides gain
proportional to the rate of change of
the speed feedback. The quicker the
error changes, the stronger the gain
from the differentiator. The gain is
proportional with the speed at which
errors change. Setting this parameter to
zero disables the differentiator. This
parameter is used with 1-00 Configu-
ration Mode Speed closed-loop [1]
control.
7-05 Speed PID Diff. Gain Limit
Range:
Function:
[1.0 -
Set a limit for the gain provided by the differen-
*
20.0 ]
tiator. 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
1-00 Configuration Mode Speed closed-loop [1]
control.
3
3
3-75
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