WG 6 - TC 65/SC 65C/WG 6

Fieldbus is a digital serial, multidrop, data bus for communication with low-level industrial control and instrumentation devices such as transducers, actuators and local controllers. The Physical Layer provides for transparent transmission of Data Link Layer entities across physical connections. Specifies the requirements for Fieldbus component parts. Also specifies the media and network configuration requirements necessary to ensure agreed levels of: a) data integrity before Data Link error checking; b) interoperability between devices at the Physical Layer.

Specifies interactions between remote applications in terms of: - the encoding rules that are applied to all the Application Layer Protocol Data Units (APDUs); - the formal Abstract Syntax defintiions of such APDUs; - the protocol state machine descriptions that handle the APDUs and the primitives int he correct sequence; - the mappings of the APDUs to and from the Data Link Layer services defined in IEC 61158-3. Defines the protocol provided: a) to the Fieldbus Data Link Layer at the boundary between the Application and Data Link Layers of the Fieldbus Reference Model, and b) to the System Management at the boundary between the System Management and Application Layers of the Fieldbus Reference Model.

Specified in conformance with the OSI Basic Reference Model (ISO/IEC 7498) and the OSI Application Layer Structure (ISO/IEC 9545). Specifies interactions between remote applications in terms of - an abstract model for defining application resources capable of being manipulated by users via the use of FAL Services; - the primitives associated with each FAL Service; - the parameters associated with each primitive; - the interrelationship between and the valid sequences of the primitives for each service.

Provides basic time-critical messaging communications between devices in an automation enviornment. Defines in an abstract way the externally visible service provided by the Fieldbus Data Link Layer in terms of a) the primitive actions and events of the service; b) the parameters associated with each primitive action and event, and the form which they take; and c) the interrelationship between these actions and events, and their valid sequence. The services defined are a superset of those provided by OSI Data Link Protocols as specified in ISO/IEC 8886.

Provides basic time-critical messaging communications between devices in an automation environment. Specifies: a) procedures for a single protocol for the timely transfer of data and control information; b) the structure of the Fieldbus Data Link (DL) Protocol Data Units. Provides communication opportunities to all participating data-link entities in a cyclic asynchronous and in a synchronous manner.