Daikin FVXS09NVJU, Service Manual

Page: 53 / 145

SiUS091601E Control Specification
Functions and Control 42
Initial Frequency When starting the compressor, the frequency is initialized according to the
∆
D value of the indoor
unit.
∆
D signal: Indoor frequency command
The difference between the room thermistor temperature and the target temperature is taken as the
∆
D value and is used for
∆
D signal of frequency command.
∗
OFF = Thermostat OFF
PI Control 1. P control
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.
2. I control
If the operating frequency does not change for 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.
3. Frequency control when other controls are functioning
Š
When frequency is dropping;
Frequency control is carried out only when the frequency drops.
Š
For limiting lower limit;
Frequency control is carried out only when the frequency rises.
4. Upper and lower limit of frequency by PI control
The frequency upper and lower limits are set according to the command of the indoor unit.
When the indoor or outdoor unit quiet operation command comes from the indoor unit, the upper
limit frequency is lower than the usual setting.
Temperature
difference
∆
D
signal
Temperature
difference
∆
D
signal
Temperature
difference
∆
D
signal
Temperature
difference
∆
D
signal
–2.0°C (–3.6°F)
∗
OFF 0°C (0°F) 4 2.0°C (3.6°F) 8 4.0°C (7.2°F) C
–1.5°C (–2.7°F) 1 0.5°C (0.9°F) 5 2.5°C (4.5°F) 9 4.5°C (8.1°F) D
–1.0°C (–1.8°F) 2 1.0°C (1.8°F) 6 3.0°C (5.4°F) A 5.0°C (9.0°F) E
–0.5°C (–0.9°F) 3 1.5°C (2.7°F) 7 3.5°C (6.3°F) B 5.5°C (9.9°F) F