General Frequency Control - Daikin SkyAir Service Manual

SiBE28-804
4.3

General Frequency Control

Outline After the "Starting frequency control" function has been terminated, the ideal compressor
frequency will be determined by the "General frequency control".
General The compressor operation frequency is controlled in order to keep a constant evaporation
temperature in cooling and a constant condensing temperature in heating.
The frequency can be changed every 20 seconds.The maximum frequency change = 2 steps/
change. (= max 6 steps/min)
During abnormal situations (e.g. inverter current protection) the change per step is also = 2
steps/change, but the 20 seconds interval may be decreased, so a quicker change is possible.
Note When other control functions are activated (e.g. discharge pipe control), they can change the
compressor frequency using other inputs than the ones normally being used by the "General
frequency control" function.
Cooling In cooling, the target operation frequency will be determined by the indoor
evaporating temperature.
∆
t cool = Remote controller set temperature - Indoor return air temperature.
Depending on the cooling load, the target evaporating temperature (Te) will be a value between
2°C
Heating In heating, the target operation frequency will be determined by the indoor
condensing temperature.
∆
t heat = Indoor return air temperature - Remote controller set temperature.
Depending on the heating load, the target condensing temperature (Tc) will be a value between
42°C
Functional Description
≤ ≤
Te 20°C.
≤ ≤
Tc 54°C.
Frequency Regulating Functions
∆
t and the
∆
t and the
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