Controls At Mode Changing / Start-Up - Daikin FTXS09HVJU Service Manual

Control Specification (09/12 Class)
Indoor Frequency Command (D signal)
The difference between the room temperature and the temperature set by the remote controller is
taken as the "D signal" and is used for frequency command.
Th OFF = Thermostat OFF
Frequency Initial Setting
<Outline>
When starting the compressor, or when conditions are varied due to the change of the room, the
frequency must be initialized according to the D value of the indoor unit and the Q value of the
indoor unit.
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. Frequency management when other controls are functioning
 When frequency is dropping;
 For limiting lower limit
4. Upper and lower limit of frequency by PI control
3.3

Controls at Mode Changing / Start-up

3.3.1 Preheating Operation
Operate the inverter in the open phase operation with conditions including the preheating
Outline
command from the discharge pipe temperature.
Detail Preheating ON Condition
 When the discharge pipe temperature is below 50ºF, inverter in open phase operation starts.
OFF Condition
38
D
Temperature Temperature
difference signal difference
°F(°C)
Th
0
OFF
0.9 (0.5) 1
1.8 (1.0) 2
2.7 (1.5) 3
Calculate 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 changed more than a certain fixed time, adjust the frequency up
and down according to the D value.
When the D value is small...lower the frequency.
When the D value is large...increase the frequency.
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 depending on indoor unit.
When low noise commands come from the indoor unit or when outdoor unit low noise or quiet
commands come from indoor unit, the upper limit frequency must be lowered than the usual
setting.
(The power consumption of compressor during preheating operation is 35 W.)
D
Temperature
signal differenc
°F(°C) °F(°C)
3.6 (2.0) 4 7.2 (4.0)
4.5 (2.5) 5 8.1 (4.5)
5.4 (3.0) 6 9.0 (5.0)
6.3 (3.5) 7 9.8 (5.5
SiUS04-904
D D
Temperature
signal difference signal
°F(°C)
8 10.8 (6.0)
9 11.7 (6.5)
A 12.6 (7.0)
B 13.5 (7.5)
Function and Control
C
D
E
F