Programming Guide | VLT® AutomationDrive FC 360
Enter the speed controller differentiation time. The differentiator does not 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 0 disables the differentiator. This parameter is used with
parameter 1-00 Configuration Mode [1] Speed closed loop control.
7-05 Speed PID Diff. Gain Limit
Default value: 5.0 Parameter type: Range (1.0–20.0)
Setup: All setups Conversion index: -1
Data type: Uint16 Change during operation: True
Set a limit for the gain provided by the differentiator. 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.
7-06 Speed PID Lowpass Filter Time
Default value: 10.0 ms Parameter type: Range (1.0–6000.0 ms)
Setup: All setups Conversion index: -1
Data type: Uint16 Change during operation: True
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 parameter is used with parameter 1-00 Configuration Mode [1] Speed closed loop or [2] Torque closed loop.
This parameter is useful if there is a great amount of noise in the system, see Figure 36. For example, if a time constant of 100 ms is
programmed, the cutoff frequency for the lowpass filter is 1/0.1 = 10 RAD/s, corresponding to (10/2 x π) = 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.
Practical settings of parameter 7-06 Speed PID Lowpass Filter Time taken from the number of pulses per revolutions from encoder:
Encoder PPR Parameter 7-06 Speed PID Lowpass Filter Time
512 10 ms
1024 5 ms
2048 2 ms
4096 1 ms
Danfoss A/S © 2024.01 AU275649936274en-001401 / 130R0507 | 159
To Next Page
Loading...
Need help?
General