Danfoss VLT FC 103 Programming Manual page 166

Parameter Description
28-24 Warning Level
Range: Function:
130 [10 – Selects the temperature at which a warning
*
28-26] shall be issued. The action selected in
28-25 Warning Action becomes active at this
temperature. Enter the temperature
measured in the unit selected in
28-21 Temperature Unit.
28-25 Warning Action
Option: Function:
Selects the action to be taken by the
frequency converter for discharge temper-
atures above the value programmed in
28-21 Temperature Unit but below the value
programmed in 28-26 Emergency Level.
[0] None No action. Only a warning will be issued.
[1] Decrease A warning is issued and the motor speed is
*
cooling lowered in steps of 10 Hz every 3 minutes
until the temperature either drops below the
level programmed in 28-24 Warning Level or
exceeds the level programmed in
28-26 Emergency Level.
28-26 Emergency Level
Range: Function:
145 [par. 28-24 - Selects the temperature at which an alarm
*
300] shall be issued. Enter the temperature in
the unit programmed in par. 28-21
Temperature Unit.
28-27 Discharge Temperature
Range:
0 [-2147483648 –
*
2147483648]
3.21.2 28-7* Day/ Night Control
In day-night control mode compressor runs normally
during day time while it runs with increased setpoint
during night time. The condenser fans run normally during
day time while they run with reduced maximum speed
limit during night time. There are three sources of day or
night indication in the frequency converter. Digital Input
(parameter group 5-1*), Timed Actions (parameter group
23-*) and LON Bus (parameter group 28-7*).
The Day-Night control action is active if 20-25 Setpoint Type
is set to 'Fixed with Night Setback'.
28-71 Day/ Night Bus Indicator
Range: Function:
0 [0 - 1] This parameter is written by the LON Bus period-
*
ically to indicate day or night. This is a read only
parameter on LCP. 1 indicates night and 0 indicates
day.
®
VLT Refrigeration Drive Programming Guide
Function:
Returns the actual value of the
discharge temperature.
®
MG16H102 - VLT is a registered Danfoss trademark
28-72 Enable Day/ Night via Bus
Range: Function:
0 [0 - 1] This parameter enables or disables usage of
*
28-71 Day/Night Bus Indicator. If this parameter is set
to [0] Disable then the value in 28-71 Day/Night Bus
Indicator is discarded in day-night control. If this
parameter is set to [1] Enable then the value in
28-71 Day/Night Bus Indicator is considered in day-
night control. If the day night signal is not received
via bus the day/night indication can be
programmed via digital inputs.
28-73 Night Setback
Range: Function:
0 [0 – (3-03 – 3-02) ] This parameter defines the value by
*
which the compressor setpoint should
be increased, during night.
28-74 Night Speed Drop
Range: Function:
0 [0 – (4-13 – This parameter defines the value by which
*
4-11) ] the maximum speed limit of the condenser
fans should be lowered during night. The
range of the value is from 0 to difference of
4-13 Motor Speed High Limit [RPM] and
4-11 Motor Speed Low Limit [RPM].
28-75 Night Speed Drop Override
Range: Function:
0 [-1000000.000 – This parameter defines a limit on the
*
1000000.000 ] condenser feedback (pressure) when night
action is active. If condenser feedback is
more than the value set in this parameter,
then night action is deactivated (if already
active) and day action is activated. A
value of zero in this parameter means
that night speed drop will be active
independent of condenser pressure.
3.21.3 28-8* P0 Optimization
The FC 103 supports the VLT Refrigeration Drive P0
Optimisation feature. This enables automatic adaptation of
the suction pressure to optimally match the system's
actual load.
To enable this function 20-25 Setpoint Type must be set to
"Floating". The frequency converter now accepts setpoint
changes from the LON bus. The frequency converter
assures that the set minimum and maximum limits for the
feedback suction pressure are observed.
28-81 dP0 Offset
Range: Function:
-999999.9 - [] The value of the parameter is added to the
999999.9 setpoint provided 20-25 Setpoint Type is
programmed to [2] Floating. The unit of the
parameter is shown as Kelvin indicating that
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