Main Functions SiBE041134EB18 Functions 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 thetemperature 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 PrincipleControlParametersThe 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 temperatureThe 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 tocontrol the rotation speed of the compressor. The following table explains the conversionprinciple: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 increase of refrigerant circulation. This leads to a larger amount of heat exchangeper unit. When the frequency decreases, the rotation speed of the compressor decreasesresulting in a decrease of refrigerant circulation. This leads to a smaller amount of heatexchange per unit.
