Frequency Control - Daikin FTKS20CVMB Service Manual

SiENBE04-401A
3.2

Frequency Control

Frequency will be 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
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
Input current, discharge pipes, freeze-up protection, dew prevention, fin thermistor temperature.
1.2 Indoor frequency command
Function and Control
the temperature set by the remote control.)
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, peak cutting, freeze-up protection, 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, peak cutting, 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 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.
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
Four-way valve operating compensation, etc. (*)
FMIN
*; only for heat pump model
Control Specification
Target frequency
(R2831)
59