Danfoss VLT Compressor Drive CDS 803 Design Manual page 9

Introduction
Bus reference
A signal transmitted to the serial communication port (FC
port).
Preset reference
A defined preset reference to be set from -100% to +100%
of the reference range. Selection of 8 preset references via
the digital terminals.
Ref
MAX
Determines the relationship between the reference input at
100% full scale value (typically 10 V, 20 mA) and the
resulting reference. The maximum reference value set in
parameter 3-03 Maximum Reference.
Ref
MIN
Determines the relationship between the reference input at
0% value (typically 0 V, 0 mA, 4 mA) and the resulting
reference. The minimum reference value set in
parameter 3-02 Minimum Reference.
Miscellaneous
Analog inputs
The analog inputs are used for controlling various
functions of the frequency converter.
There are 2 types of analog inputs:
•
Current input, 0–20 mA, and 4–20 mA.
•
Voltage input, 0–10 V DC.
Analog outputs
The analog outputs can supply a signal of 0–20 mA, 4–20
mA, or a digital signal.
Automatic Motor Adaptation, AMA
AMA algorithm determines the electrical parameters for
the connected compressor at standstill.
Digital inputs
The digital inputs can be used for controlling various
functions of the frequency converter.
Digital outputs
The frequency converter features 2 solid-state outputs that
can supply a 24 V DC (maximum 40 mA) signal.
Relay outputs
The frequency converter features 2 programmable relay
outputs.
ETR
Electronic thermal relay is a thermal load calculation based
on present load and time. Its purpose is to estimate the
compressor temperature.
Initializing
If initializing is carried out (parameter 14-22 Operation
Mode), the programmable parameters of the frequency
converter return to their default settings.
Parameter 14-22 Operation Mode does not initialize
communication parameters.
MG18N202
Design Guide
Intermittent duty cycle
An intermittent duty rating refers to a sequence of duty
cycles. Each cycle consists of an on-load and an off-load
period. The operation can be either periodic duty or none-
periodic duty.
LCP
The local control panel (LCP) makes up a complete
interface for control and programming of the frequency
converter. The control panel is detachable and can be
installed up to 3 m (9.8 ft) from the frequency converter,
that is, in a front panel with the installation kit option.
lsb
Least significant bit.
MCM
Short for Mille Circular Mil, an American measuring unit for
cable cross-section. 1 MCM ≡ 0.5067 mm
msb
Most significant bit.
On-line/Off-line parameters
Changes to on-line parameters are activated immediately
after the data value is changed. To activate the off-line
parameters, press [OK].
PI controller
The PI controller maintains the desired speed, pressure,
temperature, and so on, by adjusting the output frequency
to match the varying load.
RCD
Residual current device.
Set-up
Parameter settings in 2 set-ups can be saved. Change
between the 2 parameter set-ups and edit 1 set-up, while
another set-up is active.
Slip compensation
The frequency converter compensates for the compressor
slip by giving the frequency a supplement that follows the
measured compressor load keeping the compressor speed
almost constant.
Smart logic control (SLC)
The SLC is a sequence of user-defined actions executed
when the associated user-defined events are evaluated as
true by the SLC.
Thermistor
A temperature-dependent resistor placed where the
temperature is to be monitored (frequency converter or
compressor).
Trip
A state entered in fault situations, for example, if the
frequency converter is subject to an overtemperature or
when the frequency converter is protecting the
compressor, 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
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