Output modules plc explanation

output module plc, known as members, is a collection of individually named and independently able to complete certain functions of plc program logic controller statements (ie, aggregate program code and data structures). It has two basic characteristics: internal features and external features. Wherein the external plc digital input output module module with means to contact the external environment (i.e., program modules or other way to call the module, including input and output parameters, global variables referenced) and functional modules; internal environment is the internal characteristics of the module having the characteristics (i.e., the local module data and program codes).