Frequency Control - Daikin FTXS30LVJU Service Manual

Control Specification
3.2

Frequency Control

Outline Frequency is determined according to the difference between the room thermistor temperature and
the target temperature.
The function is explained as follows.
1. How to determine frequency
2. Frequency command from the indoor unit (Difference between the room thermistor temperature
3. Frequency initial setting
4. PI control
Detail
How to Determine Frequency
The compressor's frequency is determined by taking the following steps.
For Cooling Only Model
1. Determine command frequency
 Command frequency is determined in the following order of priority.
2. Determine upper limit frequency
 The minimum value is set as an upper limit frequency among the frequency upper limits of the
3. Determine lower limit frequency
 The maximum value is set as a 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.
For Heat Pump Model
1. Determine command frequency
 Command frequency is determined in the following order of priority.
43
and the target temperature)
When the shift of the frequency is less than zero (ΔF<0) by PI control,
the target frequency is used as the command frequency.
Upper limit frequency
Command frequency
Initial frequency Lower limit frequency
PI control
Defrost control (∗)
1. Forced cooling
2. Indoor frequency command
following functions:
Compressor protection, input current, discharge pipe temperature, freeze-up protection.
following function:
Pressure difference upkeep.
1. Limiting defrost control time
2. Forced cooling
3. Indoor frequency command
FMAX
Limit frequency
Skip control
Four way valve operating compensation (∗), etc.
FMIN
(∗): only for heat pump models
Dropping function
Input current control, etc.
Upper limit function
Compressor protection function
Target frequency
Lower limit function
Function and Control
SiUS091133
(R14717)