Daikin FTXG25CVMAW, Service Manual

Page: 38 / 196

Si04-402A Control Specification
Function and Control 29
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
the temperature set by the remote controller.)
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
„
Command frequency will be determined in the following order of priority.
1.1 Limiting frequency by drooping function
„
Input current, discharge pipes, peak cutting, freeze-up protection, dew prevention, fin
thermistor temperature.
1.2 Limiting defrost control time
1.3 Forced cooling
1.4 Indoor frequency command
2. Determine upper limit frequency
„
Set a minimum value as an upper limit frequency among the frequency upper limits of the
following functions:
Compressor protection, input current, discharge pipes, peak cutting, freeze-up protection,
defrost.
3. Determine lower limit frequency
„
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.
4. Determine prohibited frequency
„
There is a certain prohibited frequency such as a power supply frequency.
Command frequency Limit frequency
Skip control
Upper limit function
Compressor protection function
Lower limit function
Four-way valve operating compensation, etc. (*) Initial frequency
PI control
Defrost control (*)
Drooping function
Input current control, etc.
Upper limit frequency
FMAX
Lower limit frequency
FMIN
Target frequency
Command frequency X repeats when frequency becomes lower
Frequency changes by PI control < repeats when frequency becomes lower
*; only for heat pump model
(R2831)