Frequency Control - Daikin FTXS20G2V1B Service Manual

SiENBE04-808_A
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
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
Š Command frequency is determined in the following order of priority.
1. Forced cooling
2. Indoor frequency command
2. Determine upper limit frequency
Š The minimum value is set as an upper limit frequency among the frequency upper limits of
3. Determine lower limit frequency
Š The maximum value is set as an lower limit frequency among the frequency lower limits of
4. Determine prohibited frequency
Š There is a certain prohibited frequency such as a power supply frequency.
For Heat Pump Model
1. Determine command frequency
Š Command frequency is determined in the following order of priority.
1. Limiting defrost control time
2. Forced cooling
3. Indoor frequency command
Function and Control
temperature 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 Limit frequency
Lower limit frequency
Initial frequency
PI control Defrost
control (∗)
the following functions:
Compressor protection, input current, discharge pipe temperature, freeze-up protection.
the following function:
Pressure difference upkeep.
Drooping function
Input current control, etc.
Compressor protection function
FMAX
Skip control
Four way valve operating compensation (∗), etc.
FMIN
(∗): only for heat pump model
Control Specification
Upper limit function
Target frequency
Lower limit function
(R11592)
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