Control Specification; Mode Hierarchy; Frequency Control - Daikin FTKM-U Series Service Manual

SiMX042215E

3. Control Specification

3.1

Mode Hierarchy

Outline
The air conditioner control has normal operation mode, forced operation mode, and power
transistor test mode for installation and servicing.
Details
Note
Unless specified otherwise, dry operation command is regarded as cooling operation.
3.2

Frequency Control

Outline
The compressor frequency is determined according to the difference between the room
thermistor temperature and the target temperature.
Details
1. Determine command frequency
2. Determine upper limit frequency
3. Determine lower limit frequency
Part 4 Functions and Control
Air conditioner control mode
Forced operation mode
Power transistor test mode
Normal operation mode
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
Command frequency is determined in the following order of priority.
(1) Forced cooling
(2) Indoor frequency command
The minimum value is set as the upper limit frequency among the frequency upper limits of
the following functions:
Compressor protection, input current, discharge pipe temperature, freeze-up protection.
The maximum value is set as the lower limit frequency among the frequency lower limits of
the following function:
Pressure difference upkeep.
Forced cooling operation (for pump down operation)
Fan
Cooling (includes drying)
Stop (indoor unit: OFF)
Input current control, etc.
FMAX
Skip control
FMIN

Control Specification

(R20475)
Dropping function
Upper limit function
Compressor protection function
Target frequency
Lower limit function
(R12230)
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