Controls At Mode Changing / Start-Up - Daikin FTXG25CVMAW Service Manual

Control Specification
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
Frequency Initial Setting
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, air flow rate and other factors.
PI Control
1. P control
2. I control
3. Frequency management when other controls are functioning
4. Upper and lower limit of frequency by PI control
3.3

Controls at Mode Changing / Start-up

3.3.1 Preheating Operation
Outline Operate the inverter in the open phase operation with the conditions including the preheating
command (only for heat pump model) from the discharge pipe temperature.
Detail Preheating ON Condition
OFF Condition
30
∆D
Temperature Temperature
difference signal
∗Th
0
OFF
0.5 1
1.0 2
1.5 3
Outline
(Determine Frequency Up / Down by ∆D Signal)
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 change more than a certain fixed time, adjust the frequency
up and down according to the ∆D value, obtaining the fixed ∆D value.
When the ∆D value is small...lower the frequency.
When the ∆D value is large...increase the frequency.
When frequency is drooping;
Frequency management is carried out only when the frequency droops.
For limiting lower limit
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.
When the discharge pipe temperature is below 10ºC, inverter in open phase operation
starts.
When the discharge pipe temperature is higher than 12ºC, inverter in open phase operation
stops.
∆D
Temperature
difference signal difference
2.0 4
2.5 5
3.0 6
3.5 7
∆D
Temperature
signal difference
4.0 8 6.0
4.5 9 6.5
5.0 A 7.0
5.5 B 7.5
Function and Control
Si04-402A
∆D
signal
C
D
E
F