Manufacturing Automation Protocol (MAP)

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Fabiana Gagliardi
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1 Manufacturing Automation Protocol (MAP) Sviluppato specificatamente per comunicazioni tra computer in un ambiente di produzione industriale Nel 1980 General Motors decide di iniziare lo sviluppo di un protocollo di rete per scambio di dati veloce e senza rumore. Questo schema intendeva fornire uno standard comune per tutte le apparecchiature al fine di semplificare la loro integrazione Nel 1985 GM capì che non poteva realizzare il CIM in questo modo: solo il 15% di dispositivi programmabili potevano comunicare Nessun fornitore poteva soddisfare tutte le aspettative e più fornitori causavano incompatibilità al livello delle comunicazioni

Questo schema intendeva fornire uno standard comune per tutte le apparecchiature al fine di semplificare la loro integrazione Nel 1985 GM capì che non poteva

2 MAP Problemi: 1. Difficoltà nel convincere I fornitori dei vari paesi ad aderire ad un singolo standard 2. Gli standards sono complessi ed è difficoltoso e costoso sviluppare hardware e software 3. Vesioni 2.1 e 2.2 lasciavano l application-layer sotto-definito, solo nella versione 3.0 (1987) fu completamente definito: sorsero ulteriori disaccordi 4. Il protocollo MAP non è chiaramente definito in un unico documento FullMAP 3.0 (1987) MiniMap (1988) è una versione contenente solo I livelli 1,2 e 7 (non full OSI standard) ed è un architettura ridotta carrier band, single channel più veloce ed efficiente utilizzato per comunicare con I dispositivi Una versione del MAP, EPA (Enhanced Performance Architecture) è stata sviluppata, ed è supportata, dalla industria del controllo di processo (Full MAP in parallelo al MiniMAP) nel 1988.

Il protocollo MAP non è chiaramente definito in un unico documento FullMAP 3.

3 1. Broadband MAP Physical Layer 1. many simultaneous communications on same wire at same time, using varied frequencies for transmit channels and receive channels. 2. uses a head end re-modulator to retransmit the signal 3. each station needs MAP hardware 4. for very large factories 5. uses a 1 inch (2.5 cm) thick cable 6. maximum 10 Megabits/sec. per channel 2. Carrierband 1. uses smaller cables 2. less expensive 3. rate of 5 to 10 Megabits second (single channel)

receive channels. 2. uses a head end re-modulator to retransmit the signal 3. each station needs MAP hardware 4.

4 MAP Data Link Layer Real time response was required, so token passing is used If a token passing ring is broken, the computers will wait, and eventually each half of the broken ring will have tokens being passed Extensive algorithms have been developed for control of token passing, and resolution of conflicts Preferred Standards Preferred LAN is IEEE token-passing bus. Uses standard ISO network, transport, session, and presentation layers CNMA has lobbied for the inclusion of Ethernet (IEEE 802.3) as an alternative for the standard

token passing, and resolution of conflicts Preferred Standards Preferred LAN is IEEE 802.4 token-passing bus.

5 MAP Application Layer 1. FTAM (File Transfer Access Method) for file transfer 2. MMS (Manufacturing Message System) for content of messages bound for robotic equipment 3. ACSE (Association Control for Service Elements) for program to program communication The set of protocols should make communication between heterogeneous devices, not only in moving data around, but also in communication the meaning of that data

ACSE (Association Control for Service Elements) for program to program communication The set of

6 MAP Layers vs. ISO/OSI

7 MMS modeling The dominant aspect of MMS (Manufacturing Message Specification ISO/IEC 9506 Part I) is the concept of modeling MMS defines models that describe the way in which resources are made available and the way in which these resources are accessed. At the center of the MMS modeling concept are: the Virtual Manufacturing Device (VMD) abstract object models

resources are made available and the way in which these resources are accessed.

8 Virtual Manufacturing Device (VMD) The VMD describes the externally visible behavior of an MMS device when it makes resources (i.e., data table memory, program files) available to other MMS devices Assume, for example, that an MMS device exists and it makes system data table memory available to other MMS devices. It is the VMD that describes the way in which that MMS device makes the data table memory available This mapping of a device to the VMD model establishes a device as a virtual device on the MAP network, allowing it to be accessed by other virtual devices through the use of MMS services. Note that the VMD model theoretically exists within an MMS device

devices Assume, for example, that an MMS device exists and it makes system data table memory available to other MMS devices.

9 The MMS Abstract Object Models MMS also defines a series of abstract object models that describe the externally visible behavior associated with a particular MMS service or group of services The concept of object models is entirely abstract within the MMS specification, but represents real resources within a system This results in a standard external view of all MMS devices that make system resources available, but allows each MMS device to implement the model in a manner that is appropriate for the system The models define abstract objects which are part of the VMD An application program calls on the MMS services associated with a particular object to perform operations on that object.

external view of all MMS devices that make system resources available, but allows each MMS device to implement the model in a manner that is appropriate for the system The

10 TOP (Technical and Office Protocol) TOP (Technical and Office Protocols) is designed for the office environment. Lanciato dalla BOEING per il CAD distribuito nel 1985 TOP 3.0 nel 1987 Layers 1 and 2 Preferred LAN is IEEE Ethernet, But allows for Token Bus (IEEE 802.4) and Token Ring (IEEE 802.5). Fibre optical media will be added when they are defined Layers 3-6 uses same ISO standards for network, transport, session and presentation layers that MAP uses

3 Ethernet, But allows for Token Bus (IEEE 802.4) and Token Ring (IEEE 802.5).

11 TOP Application Layer ACSE and FTAM are the same as MAP, MMS is not included (MHS) CCITT X.400 message handling service provides electronic mail transfers of all types of documents ISO Virtual terminal protocol to allow a terminal on any machine to log onto any other machine. ODA/ODIF (ISO Office Document Architecture and Office Document Interchange Format) To permit formatted documents to be transmitted independently of the package used to create them. (Text, and Raster or Line graphics) CGM (ISO Computer Graphics Metafile) to permit the exchange of geometrical graphics IGES (ANSI Initial Graphics Exchange Standard) to exchange product design information among CAD/CAM workstations.

12 TOP Layers vs. ISO/OSI

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