Control Specification SiMT041509E33 Function and Control3.2 Frequency ControlOutline The compressor frequency is determined according to the difference between the roomthermistor temperature and the target temperature.Detail For Cooling Only Model1. Determine command frequencyCommand frequency is determined in the following order of priority.1. Forced cooling2. Indoor frequency command2. Determine upper limit frequencyThe minimum value is set as an upper limit frequency among the frequency upper limits ofthe following functions:Compressor protection, input current, discharge pipe temperature, freeze-up protection.3. Determine lower limit frequencyThe maximum value is set as a lower limit frequency among the frequency lower limits of thefollowing function:Pressure difference upkeep.4. Determine prohibited frequencyThere is a certain prohibited frequency such as a power supply frequency.For Heat Pump Model1. Determine command frequencyCommand frequency is determined in the following order of priority.1. Limiting defrost control time2. Forced cooling3. Indoor frequency command2. Determine upper limit frequencyThe minimum value is set as an upper limit frequency among the frequency upper limits ofthe following functions:Compressor protection, input current, discharge pipe temperature, heating peak-cut, freeze-up protection, defrost control.3. Determine lower limit frequencyThe maximum value is set as a lower limit frequency among the frequency lower limits of thefollowing functions:Four way valve operation compensation, draft prevention, pressure difference upkeep.Command frequency Limit frequency Skip controlLower limit functionFour way valve operation compensation (∗), etc.Initial frequencyPI controlDefrost control (∗)Dropping functionInput current control, etc.Upper limit functionCompressor protection functionUpper limit frequencyFMAXLower limit frequencyFMINTarget frequency(R17857)When the shift of the frequency is less than zero (∆F<0) by PI control,the target frequency is used as the command frequency.(∗): only for heat pump models
