Yasuhisa Shiobara

Advanced Map For Real-Time Process Control

MAP, a communications protocol for factory automation proposed by General Motors [1], has been accepted by users throughout the world and is rapidly becoming a user standard. In fact, it is now a LAN standard for factory automation. MAP is intended to interconnect different devices, such as computers and programmable devices, made by different manufacturers, enabling them to exchange information. It is based on the OSI intercomputer com-munications protocol standard under development by the ISO. With progress and standardization, MAP is being investigated for application to process control fields other than factory automation [2]. The transmission response time of the network system and centralized management of data exchanged with various devices for distributed control are import-ant in the case of a real-time process control with programmable controllers, computers, and instruments connected to a LAN system. MAP/EPA and MINI MAP aim at reduced overhead in protocol processing and enhanced transmission response. If applied to real-time process control, a protocol based on point-to-point and request-response transactions limits throughput and transmission response. This paper describes an advanced MAP LAN system applied to real-time process control by adding a new data transmission control that performs multicasting communication voluntarily and periodically in the priority order of data to be exchanged.

Distributed control system utilizing a MAP-based LAN

Abstract We developed the ADMAP ADvanced MAP) system as a local area network for our Distributed Instrumentaion Control System (DCS) with a broadcast communications function. ADMAP is an open system based on the Manufacturing Automation Protocol (MAP), which is advancing as an international standard, but also providing real-time performance, which is weak in MAP. The new MAP-based LAN can be used not only for electrical and computer control. This paper describes the new MAP-based LAN and discusses distributed control systems using this LAN to integrate instrumentation, electrical, and computer controls.