Frequency Control - Daikin FTX50GV1B Service Manual

Control Specification
3.2

Frequency Control

Outline The compressor frequency is determined according to the difference between the room
thermistor temperature and the target temperature.
Detail 1. Determine command frequency
2. Determine upper limit frequency
3. Determine lower limit frequency
4. Determine prohibited frequency
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When the shift of the frequency is less than zero (∆F<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
Command frequency is determined in the following order of priority.
1. Limiting defrost control time
2. Forced cooling
3. Indoor frequency command
The minimum value is set as an upper limit frequency among the frequency upper limits of
the following functions:
Compressor protection, input current, discharge pipe temperature, heating peak-cut, freeze-
up protection, defrost.
The maximum value is set as a lower limit frequency among the frequency lower limits of the
following functions:
Four way valve operation compensation, draft prevention, pressure difference upkeep.
There is a certain prohibited frequency such as a power supply frequency.
Dropping function
Input current control, etc.
FMAX
Compressor protection function
Skip control
FMIN Four way valve operation compensation, etc.
SiBE041029EC
Upper limit function
Target frequency
Lower limit function
Function and Control
(R18023)