Danfoss VLT 5000 Series Operating Instructions

VLT
®
5000 Series
If the integral time is long, major deviations from
the required set point may occur, since the
process regulator will take a long time to regulate
in relation to a given error.
442 Process PID differentiation time
(PROC. DIFF. TIME)
Value:
0.00 (OFF) - 10.00 sec.
✭ 0.00 sec.
Function:
The differentiator does not react to a constant error.
It only provides a gain when the error changes.
The quicker the error changes, the stronger the
gain from the differentiator.
The gain is proportional to the speed at which
the error changes.
Used together with Process control, closed
loop (parameter 100).
Description of choice:
Quick control is obtained with a long differentiation
time. However, this time may become too long,
which can make the process unstable.
443 Process PID diff. gain limit
(PROC. DIFF. GAIN)
Value:
5.0 - 50.0
✭ 5.0
Function:
It is possible to set a limit for the differentiator gain.
The differentiator gain will increase if there are fast
changes, which is why it can be beneficial to limit
this gain, thereby obtaining a pure differentiator gain
at slow changes and a constant differentiator gain
where quick changes to the error occur.
Used together with Process control, closed
loop (parameter 100).
Description of choice:
Select a limit to differentiator gain as required.
444 Process PID lowpass filter time
(PROC FILTER TIME)
Value:
0.01 - 10.00
✭ 0.01
Function:
Oscillations on the feedback signal are dampened
by the lowpass filter in order to reduce their impact
on the process control. This can be an advantage
e.g. if there is a lot of noise on the signal.
Used together with Process control, closed
loop (parameter 100).
Description of choice:
Select the desired time constant (τ).Ifatimeconstant
(τ) of 100 ms is programmed, the break frequency
for the lowpass filter will be 1/0.1 = 10 RAD/sec.,
correspondingto(10/2xπ)=1.6Hz.
The process regulator will thus o
nly regulateafeedback
signal that varies by a frequency lower than 1.6 Hz. If
the feedback signal varies by a higher frequency than
1.6 Hz, the Process regulator will not react.
445 Flying start
(FLYING START)
Value:
✭Off (DISABLE)
[0]
On (ENABLE)
[1]
Function:
This function makes it possible to catch spinning motor,
which is spinning freely because of a mains drop-out.
Description of choice:
Select Disable if this function is not required. Select
Enable if the frequency converter is to be able to
‘catch’ and control a spinning motor.
446 Switching pattern
(SWITCH PATTERN)
Value:
60° AVM (60° AVM)
[0]
✭SFAVM (SFAVM)
[1]
Function:
Choose between two different switching patterns:
60° AVM and SFAVM.
Description of choice:
Select60° AVM if the option of using a switching
frequency up to 14/10 kHz is required. Derating
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.51.A9.02 - VLT is a registered Danfoss trademark
148

Danfoss VLT 5000 Series Specifications

General

Brand	Danfoss
Model	VLT 5000 Series
Category	DC Drives
Language	English