Frequency Control - Daikin FTKN09NMVJU Service Manual

Control Specification
3.2

Frequency Control

Outline The compressor frequency is determined according to the difference between the room thermistor
temperature and the target temperature.
Detail For Cooling Only Model
1. Determine command frequency
2. Determine upper limit frequency
3. Determine lower limit frequency
4. Determine prohibited frequency
For Heat Pump Model
1. Determine command frequency
35
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
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 an upper limit frequency among the frequency upper limits of the
following functions:
Compressor protection, input current, discharge pipe temperature, freeze-up protection.
The maximum value is set as a lower limit frequency among the frequency lower limits of the
following function:
Pressure difference upkeep.
There is a certain prohibited frequency such as a power supply frequency.
Command frequency is determined in the following order of priority.
1. Limiting defrost control time
2. Forced cooling
3. Indoor frequency command
Input current control, etc.
FMAX
Limit frequency
Skip control
FMIN Four way valve operation compensation (∗), etc.
(∗): only for heat pump models
Dropping function
Upper limit function
Compressor protection function
Target frequency
Lower limit function
Function and Control
SiUS041501E
(R17857)