Implementation of a Virtual Factory Communication System using the Manufacturing Message Speci cation Standard
Wook Hyun Kwon‡
and Zygmunt J. Haas
School of Electrical and Computer Engineering
208 Phillips Hall, Cornell University, Ithaca, NY 14853 Tel. : 607-255-0017, Fax. : 607-254-4565, Email:firstname.lastname@example.org
Engineering Research Center for Advanced Control Instrumentation, School of Electrical and
Computer Eng., Seoul National University, Seoul, Korea 151-742
In this article, we describe the implementation of a virtual factory communication system using the manufac- turing message specification (MMS) standard and its companion standards (MMS-CS). In particular, a number of virtual networked machines based on the MMS-CS standard are designed and implemented for the virtual factory environment. Additionally, the MMS internet monitoring system (MIMS) is implemented for the virtual experiments and remote education of MMS users.
Keywords: Manufacturing message specification, MMS companion standards, MMS Internet Monitoring System, Virtual factory communication system, On-line monitoring system
For interconnection purposes, a factory automation (FA) system can be combined with various sensors, controllers, and heterogeneous machines using a common message specification. In particular, interconnection of heterogenous machines through a common message specification promotes flexibility and interoperability.
For this reason, the manufacturing message speci cation (MMS) standard have been developed. The stan- dard specifies a sets of communication primitives and communication protocols for the factory communication environment. In particular, the MMS standard specifies various functionalities of the di erent FA devices in a compatible way. Thus, users of MMS applications have to use functions from only one unique set of func- tionalities to operate various kinds of automation machines. Moreover, the di erent automation machines can communicate among themselves through the standard automation language. This enables transition from the traditional centralized control to the distributed control systems.
The MMS standard is composed of the common standards   and the MMS companion standard (MMS- CS). The MMS-CS includes device-dependent specifications for a robot , numerical controller (NC) , programmable logic controller (PLC) , and process control (PC) . In its initial stage, the MMS standard was developed for an application layer of the manufacturing automation protocol (MAP) . Nowadays, MMS have been implemented on top of the TCP/IP protocol suite and is used as a reference model for industrial network or other message protocols, such as the home network protocol . In particular, MMS is implemented in a minimized form as the application layer for Profibus (Process Fieldbus)  and Field Instrumentation Protocol (FIP) .
A virtual factory environment can be used to examine the correctness of an implementation and as a test solution of an FA system prior to installing the system in a real factory communication environment  . furthermore, by using the virtual factory communication system, developing time and costs can be minimized. In addition, it can be used as a training tool of MMS users. In this article, the virtual factory communication system was designed and implemented with the use of the MMS standards and its CS part.
Researches in the MMS technology include application of factory devices, middleware, and multimedia com- munication. In , a real NC machine was implemented using the MMS-enabled application program. In , MMS with common object request broker architecture (CoRBA) was studied. Modified architecture was pro- posed for multi-media communication in an FA system  . The performance evaluation and an analysis methodology of the MMS standard have been studied as well   . However, to the best knowledge of