Parameters: 7-** Controllers - Danfoss VLT AutomationDrive FC 302 Programming Manual

Parameter Descriptions

3.9 Parameters: 7-** Controllers

3.9.1 7-0* Speed PID Ctrl.
7-00 Speed PID Feedback Source
3 3
Option:
[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
NOTICE
If separate encoders are used (FC 302 only) the ramp
settings parameters in the following parameter groups:
3-4*, 3-5*, 3-6*, 3-7* and 3-8* must be adjusted
according to the gear ratio between the 2 encoders.
7-02 Speed PID Proportional Gain
Range:
Size [0 -
related 1 ]
*
108
VLT
Function:
NOTICE
This parameter cannot be
adjusted while the motor is
running.
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 parameter 1-02 Flux Motor
Feedback Source.
Function:
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
parameter 1-00 Configuration Mode [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 3 decimals.
For a selection with 4 decimals, use
parameter 3-83 Quick Stop S-ramp Ratio at
Decel. Start.
®
AutomationDrive FC 301/302 Programming Guide
7-03 Speed PID Integral Time
Range:
Size
related 20000
*
ms]
7-04 Speed PID Differentiation Time
Range:
Size
related
*
7-05 Speed PID Diff. Gain Limit
Range:
5 [1 -
*
20 ]
7-06 Speed PID Lowpass Filter Time
Range:
Size
related - 100
*
ms]
MG33MI02 - Rev. 2013-11-20
Function:
[1.0 - 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
parameter 1-00 Configuration Mode.
Function:
[0 - Enter the speed controller differentiation
200 time. The differentiator does not react to
ms] 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 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
parameter 1-00 Configuration Mode [1] Speed
closed loop control.
Function:
Set a limit for the gain provided by the differen-
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 parameter 1-00 Configuration
Mode [1] Speed closed loop control.
Function:
[0.1 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 Illustration 3.44. For example, if a
time constant (τ) of 100 ms is programmed,
the cut-off frequency for the low-pass filter is