Frequency Control - Daikin G-Series Service Manual

Control Specification
3.2

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 Heat Pump Model
1. Determine command frequency
1.1 Limiting defrost control time
1.2 Forced cooling
1.3 Indoor frequency command
2. Determine upper limit frequency
3. Determine lower limit frequency
4. Determine prohibited frequency
80
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.
Set a minimum value as an upper limit frequency among the frequency upper limits of the
following functions:
Compressor protection, input current, discharge pipe temperature, low Hz high pressure
limit, heating peak-cut, freeze-up protection, defrost.
Set a maximum value as an lower limit frequency among the frequency lower limits of the
following functions:
Four way valve operation compensation, draft prevention, pressure difference upkeep.
There is a certain prohibited frequency such as a power supply frequency.
Drooping function
Input current control, etc.
FMAX
Compressor protection function
Skip control
FMIN Four way valve operating compensation (∗), etc.
(∗): only for heat pump model
SiBE12-933_A
Upper limit function
Target frequency
Lower limit function
Function and Control
(R11592)