Condensing Unit Controller; Advantages; Controller's Regulation Logic; Functions - Danfoss Optyma Plus Application Manuallines

Application Guidelines

6.1 Advantages

6.2 Controller's
regulation logic

6.3 Functions

6.4 Regulation reference
for condensing
temperature

6.5 Fan operation

6.6 Compressor control

Condensing unit controller

In order to provide the highest level of compressor
protection, energy efficiency and adaptation to
• Condensing pressure control in relation to
outside temperature.
• Fan speed regulation.
• On/off and variable speed regulation of the
compressor.
• Crankcase heating element control.
• Day/night controller operation.
The controller receives a signal for demanded
cooling, and it then starts the compressor.
If compressor is controlled by variable speed, the
suction pressure (converted to temperature) will
be controlled according to the set evaporating
temperature.
Condenser pressure regulation is performed
following a signal from the ambient temperature
• Control of condensing temperature.
• Control of fan speed.
• On/off control or speed regulation of the
compressor.
• Control of heating element in crankcase.
• Liquid injection into economizer port.
The controller controls the condensing
temperature in relation to the ambient
temperature. This difference is preset in the
The controller will control the fan so that the
condensing temperature is maintained at the
desired value above the ambient temperature.
The compressor is controlled by a signal at the
DI1 input. The compressor will start once the
input is connected. Three restrictions have been
implemented to avoid frequent start/stops:
- minimum ON time.
- minimum OFF time.
- time elapsed between two starts.
These three restrictions have the highest priority
during regulation, and the other functions will
wait until they are complete before regulation
can continue. When the compressor is 'locked'
variable conditions condensing unit is equipped
with specific controller.
• Built-in clock function with power reserve .
• Built-in Modbus data communication.
• Monitoring discharge temperature td.
• Oil return management control at variable speed
operation.
sensor and the set reference corresponding to
difference between condensing and ambient
temperatures. The controller will then control the
fan, which allows the condensing temperature to
be maintained at the desired value. The controller
can also control the heating element in the
crankcase so that oil is kept separate from the
refrigerant.
• Raising the condenser pressure regulation
reference during night operation.
• Both internal and external start/stop cooling.
• Safety cut-out activated via signal from
automatic safety control.
controller. It can also, via another parameter, get
increased at night.
by a restriction, this can be seen in a status
notification. DI3 input is used as a safety stop for
the compressor, an insufficient input signal will
immediately stop the compressor. The compressor
is speed-controlled with a voltage signal at the
AO2 output.
If the compressor has been running for a long
period at low speed, the speed is increased for a
short moment for the purpose of oil return.
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FRCC.PC.044.A6.02