Daikin Super Multi NX C-Series Service Manual page 101

Control Specification
2. Determine upper limit frequency
" Set a minimum value as an upper limit frequency among the frequency upper limits of the
3. Determine lower limit frequency
" Set a maximum value as an 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.
Indoor Frequency Command (∆D signal)
The difference between a room temperature and the temperature set by the remote controller
will be taken as the "∆D signal" and is used for frequency command.
∗Th OFF = Thermostat OFF
Indoor Unit Capacity (S value)
The capacity of the indoor unit is a "S" value and is used for frequency command.
Frequency Initial Setting
" Outline
When starting the compressor, or when conditions are varied due to the change of the operating
room, the frequency must be initialized according to the total of a maximum ∆D value of each
room and a total value of Q (ΣQ) of the operating room (the room in which the thermos is set to
ON).
Q value: Indoor unit output determined from indoor unit volume, air flow rate and other factors.
PI Control (Determine Frequency Up / Down by ∆D Signal)
1. P control
2. I control
3. Limit of frequency variation width
4. Frequency management when other controls are functioning
" When each frequency is drooping;
" For limiting lower limit
5. Upper and lower limit of frequency by PI control
90
following functions:
Compressor protection, input current, discharge pipes, freeze-up protection, dew prevention,
fin thermistor temperature.
following functions:
Pressure difference upkeep.
∆D
Temperature Temperature
difference signal
∗Th
0
OFF
0.5 1
1.0 2
1.5 3
Capacity
2.5 kW
3.5 kW
Calculate a total of the ∆D value in each sampling time (20 seconds), and adjust the
frequency according to its difference from the frequency previously calculated.
If the operating frequency is not change more than a certain fixed time, adjust the frequency
up and down according to the Σ∆D value, obtaining the fixed Σ∆D value.
When the Σ∆D value is small...lower the frequency.
When the Σ∆D value is large...increase the frequency.
When the difference between input current and input current drooping value is less than 1.5
A, the frequency increase width must be limited.
Frequency management is carried out only when the frequency droops.
Frequency management is carried out only when the frequency rises.
The frequency upper and lower limits are set depending on the total of S values of a room.
When low noise commands come from the indoor unit more than one room or when outdoor
unit low noise or quiet commands come from all the rooms, the upper limit frequency must
be lowered than the usual setting.
∆D
Temperature
difference signal difference
2.0 4
2.5 5
3.0 6
3.5 7
S value
25
35
∆D
Temperature
signal difference
4.0 8 6.0
4.5 9 6.5
5.0 A 7.0
5.5 B 7.5
Capacity
5.0 kW
6.0 kW
Function and Control
SiE12-411
∆D
signal
C
D
E
F
S value
50
60