Frequency Control; Control Specification (15/18/24 Class) - Daikin FTXS09HVJU Service Manual

Control Specification (15/18/24 Class)

4.2

Frequency Control

Frequency is determined according to the difference between room and set temperature.
Outline
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 the
3. Frequency command from an indoor unit.
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
 Command frequency is determined in the following order of priority.
1.1 Limiting defrost control time
1.2 Forced cooling
1.3 Indoor frequency command
2. Determine upper limit frequency
 Set a minimum value as an upper limit frequency among the frequency upper limits of the
3. Determine lower limit frequency
 Set a maximum value as an lower limit frequency among the frequency lower limits of the
4. Determine prohibited frequency
 There is a certain prohibited frequency such as a power supply frequency.
50
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 (*)
following functions:
Compressor protection, input current, discharge pipe temperature, low Hz high pressure,
heating peak-cut, freeze-up protection, defrost.
following functions:
Four-way valve operation compensation, draft prevention, pressure difference upkeep.
Dropping function
Input current control, etc.
Upper limit frequency
Upper limit function
Compressor protection function
Limit frequency Skip control
Lower limit frequency Lower limit function
FMIN Four-way valve operating compensation, etc. (*)
*; only for heat pump model
SiUS04-904
Target frequency
(R2831)
Function and Control