ČSN EN IEC 61158-4-3 ED.4   (184020) Průmyslové komunikační sítě - Specifikace sběrnice pole - Část 4-3: Specifikace protokolu datového spoje - Prvky typu 3

Anotace textu normy ČSN EN IEC 61158-4-3 ED.4   (184020)

The data-link layer provides basic time-critical messaging communications between devices in an automation environment. This protocol provides communication opportunities to a pre-selected ´master´ subset of data-link entities in a cyclic asynchronous manner, sequentially to each of those data-link entities. Other data-link entities communicate only as permitted and delegated by those master data-link entities. For a given master, its communications with other data-link entities can be cyclic, or acyclic with prioritized access, or a combina-tion of the two. This protocol provides a means of sharing the available communication resources in a fair manner. There are provisions for time synchronization and for isochronous operation.