Frequency Control - Daikin SUPER MULTI NX CTXS07JVJU Service Manual

Control Specification
3.2

Frequency Control

Outline
Frequency that corresponds to each room's capacity is determined according to the difference
between the target temperature and the temperature of each room.
The function is explained as follows.
1. How to determine frequency
2. Frequency command from an indoor unit (Difference between a room thermistor temperature
3. Frequency command from an indoor unit (The ranked capacity of the operating room)
4. Frequency initial setting
5. PI control
Detail How to Determine Frequency
The compressor's frequency is determined by taking the following steps.
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 upper limit frequency among the frequency upper limits of the
3. Determine lower limit frequency
 The maximum value is set as the 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.
55
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
Lower limit frequency
Initial frequency
PI control
Defrost control
1. Limiting defrost control time
2. Forced cooling / heating
3. Indoor frequency command
following functions:
Compressor protection, input current, discharge pipe temperature, low Hz high pressure limit,
heating peak-cut, freeze-up protection, defrost.
following functions:
Four way valve operation compensation, draft prevention, pressure difference upkeep.
Input current control, etc.
FMAX
Limit frequency
Skip control
FMIN Four way valve operating compensation, etc.
Dropping function
Upper limit function
Compressor protection function
Target frequency
Lower limit function
Function and Control
SiUS12-928_B
(R14951)