Daikin B-Series Service Manual page 89

Control Specification
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.
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, air flow rate and other factors.
PI Control
1. P control
2. I control
3. Limit of frequency variation width
78
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-up protection, 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
5.0 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.
When the difference between input current and input current drooping value is less than 1.5
A, the frequency increase width must be limited.
∆D
Temperature
difference signal difference
2.0 4
2.5 5
3.0 6
3.5 7
S value
25
35
50
∆D
Temperature
signal difference
4.0 8 6.0
4.5 9 6.5
5.0 A 7.0
5.5 B 7.5
Capacity
6.0 kW
7.1 kW
Function and Control
Si12-714
∆D
signal
C
D
E
F
S value
60
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