Daikin F-Series Service Manual page 101

Control Specification
For Cooling Only Model
1. Determine command frequency
1.1 Limiting frequency by drooping function
1.2 Indoor frequency command
2. Determine upper limit frequency
3. Determine lower limit frequency
4. Determine prohibited 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.
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 ( Σ Q) of the operating room (the room in which the thermostat is set
to ON).
Q value: Indoor unit output determined from indoor unit volume, airflow rate and other factors.
PI Control
1. P control
2. I control
90
Command frequency will be determined in the following order of priority.
Input current, discharge pipes, freeze prevention, dew prevention, fin thermistor
temperature.
Set a minimum value as an upper limit frequency among the frequency upper limits of the
following functions:
Compressor protection, input current, discharge pipes, freeze prevention, dew prevention,
fin thermistor temperature.
Set a maximum value as an lower limit frequency among the frequency lower limits of the
following functions:
Pressure difference upkeep.
There is a certain prohibited frequency such as a power supply frequency.
∆D
Temperature Temperature
difference signal
∗Th
0
OFF
0.5 1
1.0 2
1.5 3
Capacity
2.5 kW
3.5 kW
(Determine Frequency Up/Down by ∆ D Signal)
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.
∆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
Function and Control
SiBE12-712C
∆D
signal
C
D
E
F