Frequency Control - Daikin CTXU25G2V1B Service Manual

Control Specification
3.3

Frequency Control

Outline Frequency that corresponds to each room's capacity is determined according to the difference
in the temperature of each room and the temperature that is set by the remote controller.
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. (The ranked capacity of the operating room).
4. Frequency initial setting.
5. PI control.
Detail How to Determine Frequency
The compressor 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
41
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 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.
Each drooping function
Input current control, etc.
Upper limit frequency Each upper limit function
FMAX Compressor protection function
Limit frequency
Skip control
Each lower limit function
Lower limit frequency
Four way valve operating compensation, etc. (*)
FMIN
*; only for heat pump model
SiBE12-908
Target frequency
(R1375)
Function and Control