Global data structure for positioning machine controlled by PLC

Well designed data structure simplifies programming of complex systems and makes its application more efficient. The issue in proper data structure declaration in programmable logic controller (PLC) is what technique for describing parameters, commands and states of system to choose. For universal system implementation its data structure should be expandable according to the requirements of controlled application. This paper describes universal global data structure for driving multi-axis positioning machines or manipulators by B&R programmable logic controller (PLC). It is defined by hierarchically composite structure data types which can be used in all programs and parts of software. It consists of three main substructures in which PLC, motion and main program parameters, commands and state machines are described. Global structure can be transformed to control various systems which support PLCopen standard.