Control Specification
SiUS091601EA
79
Part 4 Functions and Control
(3) Indoor frequency command
2.
Determine upper limit frequency
The minimum value is set as an upper limit frequency among the frequency upper limits of the
following functions:
Compressor protection, input current, discharge pipe temperature, heating peak-cut, freeze-up
protection, defrost control.
3.
Determine lower limit frequency
The maximum value is set as an lower limit frequency among the frequency lower limits of the
following functions:
Four way valve operation compensation, draft prevention, pressure difference upkeep.
4.
Determine prohibited frequency
There is a certain prohibited frequency such as a power supply frequency.
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
D value is low, the frequency is lowered.
When
D value is high, the frequency is increased.
3.
Frequency control when other controls are functioning
When frequency is dropping:
Frequency control is carried out only when the frequency drops.
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)
12
–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)
13
–1.0°C (–1.8°F)
2
1.0°C (1.8°F)
6
3.0°C (5.4°F)
10
5.0°C (9.0°F)
14
–0.5°C (–0.9°F)
3
1.5°C (2.7°F)
7
3.5°C (6.3°F)
11
5.5°C (9.9°F)
15
Summary of Contents for FTX-N Series
Page 18: ...SiUS091601EA 13 Part 2 Specifications 1 Specifications 14 Part 2 Specifications...
Page 198: ...Check SiUS091601EA 193 Part 6 Service Diagnosis 18 24 class R24538 1 2 3 4 Multimeter...
Page 201: ...SiUS091601EA Check Part 6 Service Diagnosis 196 18 24 class R24539 DC DC W V U...
Page 229: ...SiUS091601EA Piping Diagrams Part 8 Appendix 224 RXL15QMVJU RXL18UMVJU 3D100007 3D123368...
Page 230: ...Piping Diagrams SiUS091601EA 225 Part 8 Appendix RXL24UMVJU 3D107985A...
