ČSN EN IEC 61158-3-28

This part of IEC 61987 provides This part of IEC 61158 describes basic packet communication services and models in an automation control industrial field environment. The Type 28 data-link layer provides time-critical and non-time-critical communication services. Time-critical refers to the requirement to complete specified functions between devices in a defined time window in an industrial field environment. Failure to complete specified functions within the time window can lead to failure or harm in industrial production. This document defines in an abstract way the externally visible service provided by the Type 28 fieldbus data-link layer in terms of a) function description; b) primitive actions and events with primitive sequence diagram; c) the form of externally service interface and related parameters.