Daikin SUPER MULTI NX CTXS07JVJU Service Manual page 64

SiUS12-928_B
Indoor Frequency Command (D signal)
The difference between a room thermistor temperature and the target temperature is taken as the
"D signal" and is used for frequency command.
–3.6°F (–2.0°C)
–2.7°F (–1.5°C)
–1.8°F (–1.0°C)
–0.9°F (–0.5°C)
Values depend on the type of indoor unit.
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.
Ex:
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 (Q) of the operating room (the room in which the thermos is set to ON).
Q value: Indoor unit output determined from indoor unit volume, airflow rate and other factors.
PI Control (Determine Frequency Up / Down by D Signal)
1. P control
2. I control
3. Limit of frequency increasing range
4. Frequency management when other controls are functioning
 When each frequency is dropping;
 For limiting lower limit
5. Upper and lower limit of frequency by PI control
Function and Control
D
Temperature Temperature
difference signal
Th
OFF
1 0.9°F (0.5°C)
2 1.8°F (1.0°C)
3 2.7°F (1.5°C)
Capacity
9 kBtu/h
12 kBtu/h
A total of the D value is calculated in each sampling time (20 seconds), and the frequency is
adjusted according to its difference from the frequency previously calculated.
If the operating frequency is not change more than a certain fixed time, the frequency is
adjusted according to the D value.
When the D value is low, the frequency is lowered.
When the D value is high, the frequency is increased.
When the difference between input current and input current dropping value is less than 1.5 A,
the frequency increasing range must be limited.
Frequency management is carried out only when the frequency drops.
Frequency management is carried out only when the frequency rises.
The frequency upper and lower limits are set according to the total of S values. When the indoor
unit quiet operation commands come from more than one room or when the outdoor unit quiet
operation commands come from all the rooms, the upper limit frequency is lower than the usual
setting.
D
Temperature
difference signal difference
0°F (0°C) 4 3.6°F (2.0°C)
5 4.5°F (2.5°C)
6 5.4°F (3.0°C)
7 6.3°F (3.5°C)
S value
25
35
Control Specification
D
Temperature
signal difference
8 7.2°F (4.0°C)
9 8.1°F (4.5°C)
A 9°F (5.0°C)
B 9.9°F (5.5°C)
Capacity S value
18 kBtu/h 50
24 kBtu/h 60
D
signal
C
D
E
F
56