Main Functions SiBE041213E15 Function and Control1. Main Functions1.1 Temperature ControlDefinitions ofTemperaturesThe definitions of temperatures are classified as following. Room temperature: temperature of lower part of the room Set temperature: temperature set by remote controller Room thermistor temperature: temperature detected by room temperature thermistor Target temperature: temperature determined by microcomputerTemperatureControlThe temperature of the room is detected by the room temperature thermistor. However, there isa difference between the “temperature detected by room temperature thermistor” and the“temperature of lower part of the room”, depending on the type of the indoor unit or installationcondition. Practically, the temperature control is done by the “target temperature appropriatelyadjusted for the indoor unit” and the “temperature detected by room temperature thermistor”.1.2 Frequency PrincipleMain ControlParametersThe frequency of the compressor is controlled by the following 2 parameters: The load condition of the operating indoor unit The difference between the room thermistor temperature and the target temperatureAdditionalControlParametersThe target frequency is adapted by additional parameters in the following cases: Frequency restrictions Initial settings Forced cooling operationInverter Principle To regulate the capacity, a frequency control is needed. The inverter makes it possible to alterthe rotation speed of the compressor. The following table explains the conversion principle:Target temperatureSet temperatureRoom temperatureRoom thermistor temperature(R12321)Phase Description1 The supplied AC power source is converted into the DC power source for the present.2 The DC power source is reconverted into the three phase AC power source with variablefrequency. When the frequency increases, the rotation speed of the compressor increases resultingin an increased refrigerant circulation. This leads to a higher amount of the heatexchange per unit. When the frequency decreases, the rotation speed of the compressor decreasesresulting in a decreased refrigerant circulation. This leads to a lower amount of the heatexchange per unit.
