VLT
®
2800 Series
■
Load and Motor
■
Configuration
Selection of configuration and torque characteristics
has an effect on which parameters can be seen in the
display. If
Open loop
[0] is selected, all parameters
relating to PID regulation will be filtered out. This
means that the user only sees the parameters that
are relevant for a given application.
100 Configuration
(CONFIGURATION)
Value:
✭
Speed control, open loop
(SPEED OPEN LOOP)
[0]
Speed control, closed loop
(SPEED CLOSED LOOP)
[1]
Process control, closed loop
(PROCESS CLOSED LOOP)
[3]
Function:
This parameter is used to select the configuration
to which the frequency converter is to be adapted.
This makes adaptation to a given application
simple, since the parameters not used in a given
configuration are hidden (not active).
Description of choice:
If
Speed control, open loop
[0] is selected, normal
speed control is obtained (without feedback
signal) with automatic load and slip compensation
to ensure a constant speed at varying loads.
Compensations are active, but may be disabled in
parameter 134
Load compensation
and parameter
136
Slip compensation
as required.
If
Speed control, closed loop
[1] is selected, better
speed accuracy is obtained. A feedback signal must
be added, and the PID regulator must be set in
parameter group 400
Special functions
.
If
Process control, closed loop
[3] is selected, the
internal process regulator is activated to enable precise
control of a process in relation to a given process
signal. The process signal can be set to the relevant
process unit or as a percentage. A feedback signal
must be added from the process and the process
regulator must be set in parameter group 400
Special
functions
. Process closed loop is not active if a
DeviceNet card is mounted and Instance 20/70 or
21/71 is chosen in parameter 904
Instance types
.
101 Torque characteristic
(TORQUE CHARACT)
Value:
✭
Constant torque
(CONSTANT TORQUE)
[1]
Variable torque low
(TORQUE: LOW)
[2]
Variable torque medium
(TORQUE: MED)
[3]
Variable torque high
(TORQUE: HIGH)
[4]
Variable torque low with CT start
(VT LOW CT START)
[5]
Variable torque medium with CT start
(VT MED CT START)
[6]
Variable torque high with CT start
(VT HIGH CT START)
[7]
Special motor mode
(SPECIAL MOTOR MODE)
[8]
CT = Constant torque
Function:
This parameter enables a choice of principle
for adaptation of the U/f ratio of the frequency
converter to the torque characteristic of the
load. See par. 135
U/f ratio.
Description of choice:
If
Constant torque
[1] is selected, a load-dependent U/f
characteristic is obtained, in which output voltage and
output frequency are increased at increasing loads in
order to maintain constant magnetization of the motor.
Select
Variable torque low
[2],
Variable torque
medium
[3] or
Variable torque high
[4], if the load
is square (centrifugal pumps, fans).
Variable torque - low with CT start
[5],
- medium with
CT start
[6] or
high with CT start
[7], are selected if
you need a greater breakaway torque than can be
achieved with the three first characteristics.
NB!:
Load and slip compensation are not
active if variable torque or special motor
mode have been selected.
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.E9.02 - VLT is a registered Danfoss trademark
68
