Open communication in manufacturing automation

The trend towards increasing operational flexibility and integration in manufacturing has been and will be very essential. One of the key aspects for this kind of evolution is that different kind of information and automation systems can be easily and reliably programmed or configured to communicate with each other. Specific requirements for the communication in manufacturing are discussed at first. The benefits of the standardisation of communication protocols are analysed. The guidelines for protocol layering defined in the Open System Interconnection (OSI) -reference model of International Organisation for Standardization (ISO) are presented. The historical backgrounds and the status of the MAP/TOP- and the socalled fieldbus -processes are analysed. Important application layer OSI-protocols for manufacturing are discussed: Directory Services, Network Management, File Transfer and Access Management FTAM and Manufacturing Message Specification MMS. The MMS service sets, services and protocol are described. The MAP implementation classes and ISO/IEC MMS Companion Standards (CS) are viewed. The MAP/TOP product markets and installations are analysed. MAP interfaces including MMS software are available for the most relevant computer platforms and for rather few PLC, CNC and robot controllers. The MAP interfaces and other products are still expensive. The performance of the MAP networks is rather low. This is due to the complexity of the OSI-protocols and thus heavy overhead. Any MAP/OSI boom has not emerged. There are still rather few MAP-installations. The biggest installations are in automobile industry. In Finland the integration needed can in many cases be implemented sufficiently well by tailoring the most suitable proprietary network and automation solution to satisfy the various needs in different enterprises. On the other hand the benefits of widely accepted communication and integration standards in manufacturing cannot be disputed. International standardization processes are typically of slow character. For OSI and MMS a huge amount of work has been done. Useful protocol-standards, which are satisfying real needs, have been accomplished. It is highly probable that the use of OSI/MAP/TOP and particularly MMS-products will increase and the market share will grow. The core MMS-Companion Standards are now almost ready and will contribute significantly to the growth in the OSI-markets. The new international ISO/IEC fieldbus will supplement the OSI -arsenal and it will be really important and widely used