Controls At Mode Changing/Start-Up - Daikin RX-W Series Service Manual

SiUS092230EA
PI Control
1. P control
2. I control
3. Frequency control when other controls are functioning
4. Upper and lower limit of frequency by PI control
5.3

Controls at Mode Changing/Start-up

5.3.1 Preheating Control
Outline
The inverter operation in open phase starts with the conditions of the outdoor temperature, the
discharge pipe temperature, the radiation fin temperature and the preheating command from the
indoor unit.
Details Outdoor temperature ≥ –2.5°C (27.5°F) Control A (preheating for normal state)
Outdoor temperature < –2.5°C (27.5°F) Control B (preheating of increased capacity)
Control A
 ON condition
 OFF condition
Control B
 ON condition
 OFF condition
Part 4 Functions and 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.
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.
 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.
The frequency upper and lower limits are set according to the command of the indoor unit.
When the indoor unit quiet or QUIET OUTDOOR UNIT operation command comes from the
indoor unit, the upper limit frequency is lower than the usual setting.
Discharge pipe temperature < 0°C (32.0°F)
Radiation fin temperature < 85°C (185°F)
Discharge pipe temperature > 2°C (35.6°F)
Radiation fin temperature ≥ 90°C (194°F)
Discharge pipe temperature < 10°C (50.0°F)
Radiation fin temperature < 85°C (185°F)
Discharge pipe temperature > 12°C (53.6°F)
Radiation fin temperature ≥ 90°C (194°F)
Control Specification
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