A motion control function library comprises a set of standard functional blocks integrated in a programmable integrated environment， which is vital to the rapid development of reconfigurable PAC systems. To solve the problems associated with the rapid development of functional blocks and the standardized development of control systems， the development methods and key technologies of functional blocks are investigated in this study； In addition， a motion control function library architecture based on the PLC open specification and its rapid development method are proposed. First， the servo control principle of classical electromechanical equipment is investigated and analyzed， and a series of motion control function libraries are developed via domestic programming and development tools. Subsequently， based on the idea of software-defined machines， a motion control system of mechanical and electrical equipment is constructed via graphical programming and then verified on a high-precision rotating double prism. Experimental results show that the developed functional block can complete the target motion and that the highest interpolation accuracy achievable by the autonomous controllable system is 0.3 mm. Therefore， the proposed development method for functional blocks and function library architectures can satisfy the control requirements of most electromechanical devices.