Frequency Control - Daikin Super multi NX E Series Service Manual

Control Specification
4.2

Frequency Control

Outline Frequency that corresponds to each room's capacity is determined according to the difference
between the target temperature and the temperature of each room.
The function is explained as follows.
1. How to determine frequency
2. Frequency command from an indoor unit (Difference between a room thermistor
3. Frequency command from an indoor unit (The ranked capacity of the operating room)
4. Frequency initial setting
5. PI control
Detail
How to Determine Frequency
The compressor's frequency is determined by taking the following steps.
For Cooling Only Model
1. Determine command frequency
2. Determine upper limit frequency
3. Determine lower limit frequency
4. Determine prohibited frequency
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temperature and the target temperature)
When the shift of the frequency is less than zero (∆F<0) by PI control,
the target frequency is used as the command frequency.
Upper limit frequency
Command frequency Limit frequency
Initial frequency Lower limit frequency
PI control
Defrost control (∗)
Command frequency is determined in the following order of priority.
1. Forced cooling
2. Indoor frequency command
The minimum value is set as the upper limit frequency among the frequency upper limits of
the following functions:
Compressor protection, input current, discharge pipe temperature, low Hz high pressure
limit, freeze-up protection.
The maximum value is set as lower limit frequency among the frequency lower limits of the
following functions:
Draft prevention, pressure difference upkeep.
There is a certain prohibited frequency such as a power supply frequency.
Dropping function
Input current control, etc.
FMAX
Compressor protection function
Skip control
FMIN Four way valve operation compensation (∗), etc.
(∗): only for heat pump models
SiBE121135_A
Upper limit function
Target frequency
Lower limit function
Function and Control
(R17847)