Abstract: Addressing the problems concerning the serial communication in the process of operation of the Manufacturing Execution System or MES as used by the small-sized welded pipe plant,the SPComm control device can be used to realize the serial communication of the MES.Described are such aspects as the five major function modules of the MES and the assemblies composed thereof,the process flow of the serial signal communication and the technique for realizing the communications between the pipe cut-off machines,the MES and the marking machine.