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Technical Information
3
Night temperature setpoint
This parameter defines the temperature set point for the cabinet during night operation mode. Depending on
the compressor type this parameter has a different meaning.
Fixed speed compressor: The temperature control is done by a dead band controller. This parameter defines
the cut off temperature for the compressor. The cut on temperature is this parameter plus the night
temperature difference (
57 Night temperature difference
). In case of a sensor failure, the dead band
controller runs in cycle mode.
Thermostat
off
Thermostat
on
Set point
Difference
Control Temperature
Figure 15 Fix speed control
Variable speed compressor: The temperature control is done by a PI controller. This parameter defines the
temperature set point, which is the middle of the P band. The cut off temperature (compressor off) is this
parameter minus ½ of the night temperature difference (
57 Night temperature difference
). In case of a
sensor failure the PI controller runs with 50% speed. For variable speed applications it is recommended to
use a wider band (~5K) to prevent cut offs after defrost. The cut off band (½ of the temperature difference) is
not influencing the accuracy of PI temperature control. It is only relevant in case the losses of the cabinet are
lower than the cooling capacity at minimum speed. In this case a freezing of the goods is prevented.
0%
Set point
+1/2 Difference
-1/2 Difference
100%
Speed
Figure 16 Variable speed control
4
Mean value (nighttime operation)
Selection of measuring sensors for controlling the air temperature via air inlet or air outlet during nighttime
operation.
Control temperature = air inlet + ([air outlet - air inlet] x Mean value / 100)
5
Temporary day duration
Using the button
on the display unit or a Modbus command, it is possible to trigger a time-limited daytime
operation for loading goods into the equipment during nighttime operation. After the configured amount of time
has expired, the cabinet returns to nighttime operation.
6
Condensing pressure set point
Threshold value for a cut off hybrid fans. If the pressure drops below this threshold the hybrid fan is switched
off.
7
Condensing pressure difference
The hybrid fan is activated when the setpoint value + dead band is exceeded. This function is only active if the
hybrid fan is configured for condensing pressure control.
