from the frequency converter, that is, in a front panel with
the installation kit option.
NLCP
The numerical local control panel interface for control and
programming of the frequency converter. The display is
numerical and the panel is used to show process values.
The NLCP has storing and copy functions.
lsb
Least signicant bit.
msb
Most signicant bit.
MCM
Short for mille circular mil, an American measuring unit for
cable cross-section. 1 MCM = 0.5067 mm
2
.
On-line/o-line parameters
Changes to on-line parameters are activated immediately
after the data value is changed. Press [OK] to activate
changes to o-line parameters.
Process PID
The PID control maintains speed, pressure, and
temperature by adjusting the output frequency to match
the varying load.
PCD
Process control data.
Power cycle
Switch o the mains until the display (LCP) is dark, then
turn power on again.
Power factor
The power factor is the relation between I
1
and I
RMS
.
Power factor =
3xUxI
1
cosϕ1
3xUxI
RMS
For VLT
®
Midi Drive FC 280 frequency converters, cos
ϕ
1 =
1, therefore:
Power factor =
I1xcosϕ1
I
RMS
=
I
1
I
RMS
The power factor indicates to which extent the frequency
converter imposes a load on the mains supply.
The lower the power factor, the higher the I
RMS
for the
same kW performance.
I
RMS
=
I
1
2
+ I
5
2
+ I
7
2
+ .. + I
n
2
In addition, a high power factor indicates that the dierent
harmonic currents are low.
The built-in DC coils produce a high power factor,
minimising the imposed load on the mains supply.
Pulse input/incremental encoder
An external, digital pulse transmitter used for feeding back
information on motor speed. The encoder is used in
applications where great accuracy in speed control is
required.
RCD
Residual current device.
Set-up
Save parameter settings in 2 set-ups. Change between the
2 parameter set-ups and edit 1 set-up while another set-up
is active.
SFAVM
Acronym describing the switching pattern stator ux-
oriented asynchronous vector modulation.
Slip compensation
The frequency converter compensates for the motor slip by
giving the frequency a supplement that follows the
measured motor load, keeping the motor speed almost
constant.
Smart logic control (SLC)
The SLC is a sequence of user-dened actions executed
when the associated user-dened events are evaluated as
true by the smart logic controller (parameter group 13-**
Smart Logic Control).
STW
Status word.
THD
Total harmonic distortion states the total contribution of
harmonic distortion.
Thermistor
A temperature-dependent resistor placed where the
temperature is monitored (frequency converter or motor).
Trip
A state entered in fault situations, for example, if the
frequency converter is subject to overvoltage or when it is
protecting the motor, process, or mechanism. Restart is
prevented until the cause of the fault has disappeared, and
the trip state is canceled by activating reset or, sometimes,
by being programmed to reset automatically. Do not use
trip for personal safety.
Trip lock
A state entered in fault situations when the frequency
converter is protecting itself and requiring physical
intervention, for example, if the frequency converter is
subject to a short circuit on the output. A locked trip can
only be cancelled by cutting o mains, removing the cause
of the fault, and reconnecting the frequency converter.
Restart is prevented until the trip state is cancelled by
activating reset or, in some cases, by being programmed to
reset automatically. Do not use trip lock for personal safety.
VT characteristics
Variable torque characteristics used for pumps and fans.
VVC
+
If compared with standard voltage/frequency ratio control,
voltage vector control (VVC
+
) improves the dynamics and
stability, both when the speed reference is changed and in
relation to the load torque.
60° AVM
Refers to the switching pattern 60
°
asynchronous vector
modulation.
Introduction
VLT
®
Midi Drive FC 280
6 Danfoss A/S © 12/2015 All rights reserved. MG07C102
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