64|TechniquesofAutomation&AppicationsPLCControlofTheScrewRefrigeratingCompressorXIAOFeng-hua(South-CentralUniversityforNationalities,Wuhan430074,China)Abstract:ThispaperintroducesthecontrolofthescrewrefrigeratingcompressorwiththeSiemensseriesS7-200PLC.Thefuzzycontroltechniqueisusedtocontroltherefrigeratingcapacity.Keywords:screwrefrigeratingcompressor;PLC;fuzzycontrolPLCandDCS65|TechniquesofAutomation&Appications~iA~iB~iC~iA~iB~iC~iR~iR~iA~iB~iCiR~iA~iB~iC~Α~Β~iU~UPLCandDCS66|TechniquesofAutomation&AppicationsDAT10/-=PLCandDCS67|TechniquesofAutomation&AppicationsPLCandDCS76|TechniquesofAutomation&AppicationsElectricalDrives