Frequency Control - Daikin F-Series Service Manual

Control Specification
3.2

Frequency Control

Outline Frequency will be determined according to the difference between room and set temperature.
The function is explained as follows.
1. How to determine frequency.
2. Frequency command from an indoor unit. (The difference between a room temperature and
3. Frequency command from an indoor unit.
4. Frequency initial setting.
5. PI control.
Detail How to Determine Frequency
The compressor's frequency will finally be determined by taking the following steps.
For Heat Pump Model
1. Determine command frequency
1.1 Limiting frequency by drooping function
1.2 Limiting defrost control time
1.3 Forced cooling
1.4 Indoor frequency command
2. Determine upper limit frequency
3. Determine lower limit frequency
4. Determine prohibited frequency
For Cooling Only Model
1. Determine command frequency
1.1 Limiting frequency by drooping function
1.2 Indoor frequency command
44
the temperature set by the remote controller.)
Frequency changes by PI control < repeats when frequency becomes lower
Command frequency X repeats when frequency becomes lower
Command frequency
Initial frequency
PI control
Defrost control (*)
Command frequency will be determined in the following order of priority.
Input current, discharge pipes, low Hz high pressure limit, peak cutting, freeze prevention,
dew prevention, fin thermistor temperature.
Set a minimum value as an upper limit frequency among the frequency upper limits of the
following functions:
Compressor protection, input current, discharge pipes, Low Hz high pressure, peak cutting,
freeze prevention, defrost.
Set a maximum value as an lower limit frequency among the frequency lower limits of the
following functions:
Four way valve operating compensation, draft prevention, pressure difference upkeep.
There is a certain prohibited frequency such as a power supply frequency.
Command frequency will be determined in the following order of priority.
Input current, discharge pipes, freeze prevention, dew prevention, fin thermistor
temperature.
Drooping function
Input current control, etc.
Upper limit frequency
Upper limit function
FMAX
Compressor protection function
Limit frequency
Skip control
Lower limit function
Lower limit frequency
FMIN Four-way valve operating compensation, etc. (*)
*; only for heat pump model
SiBE04-705
Target frequency
(R2831)
Function and Control