Technical data

VLT
®
2800 Series
- Flying start does not work at lower values
than 250 rpm.
451 Speed PID feedforward factor
(FEEDFORWARD FACT)
Value:
0 - 500 %
✭ 100 %
Function:
This parameter is only active if in parameter 100
Configuration the selection made is Speed regulation,
closed loop. The FF function sends a larger or smaller
part of the reference signal outside the PID controller
in such a way that the PID controller only has an
influence on part of the control signal. Any change
to the set point will thus have a direct effect on the
motor speed. The FF factor provides high dynamism
when changing the set point and less overswing.
Description of choice:
The required % value can be selected in the interval
f
MIN
-f
MAX
. Values over 100 % are used if the
set point variations are only small.
452 Controller range
(PID CONTR. RANGE)
Value:
0 - 200 %
✭ 10 %
Function:
This parameter is only active if in parameter
100 Configuration the selection made is Speed
regulation, closed loop.
The controller range (bandwidth) limits the output from
the PID controller as a % of motor frequency f
M,N
.
Description of choice:
The required % value can be selected for motor
frequency f
M,N
. If the controller range is reduced the
speed variations will be less during initial tuning.
456 Brake Voltage Reduce
(BRAKE VOL REDUCE)
Value:
0 - 25 V if 200V device
✭ 0
0 - 50 V if 400V device
✭ 0
Function:
The user sets the voltage by which the level for
resistor braking is reduced. It is only active when
resistor in parameter 400 is selected.
Description of choice:
The greater the reduction value, the faster the
reaction to a generator overload. Should only
be used if there are problems with overvoltage
in the intermediate circuit.
461 Feedback conversion
(FEEDBAC CONV.)
Value:
✭Linear (LINEAR)
[0]
Square root (SQUARE ROOT)
[1]
Function:
In this parameter, a function is selected which converts
a connected feedback signal from the process to a
feedback value that equals the square root of the
connected signal. This is used, e.g. where regulation
of a flow (volume) is required on the basis of pressure
as feedback signal (flow = constant x
).
This conversion makes it possible to set the reference
in such a way that there is a linear connection
between the reference and the flow required.
Description of choice:
If Linear [0] is selected, the feedback signal and the
feedback value will be proportional. If Square root
[1] is selected, the frequency converter translates the
feedback signal to a squared feedback value.
NB!:
Parameter groups 500 Serial communication
and 600 Service functions are not included
in this manual. Please contact Danfoss and
ask for the VLT 2800 Design Guide.
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.A9.02 - VLT is a registered Danfoss trademark
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