Overview
IEC 61158-3-19:2019 is the fourth-edition international standard that defines the data-link layer service for Type 19 fieldbus elements in industrial communication networks. It specifies the abstract services offered at the boundary between the application and data-link layers - and between the data-link layer and systems management - for time-critical messaging in automation systems. This edition (2019) cancels and replaces the 2014 edition and includes technical revisions to improve hotplug and redundancy, phase switching, and error handling.
Key topics and technical requirements
- Abstract data-link services: Defines primitives, parameters and valid sequences for externally visible services (not concrete protocol encodings).
- Time-critical communications: Targeted at applications requiring deterministic actions within defined time windows.
- Service primitives and channels:
- Acknowledged connection-oriented: Read (RD), Write (WR), Initiate_cyclic_communication (ICC), Disable_cyclic_communication (DCC).
- Unacknowledged connectionless: Write_cyclic (WRC), Send_Device_Status (SDS), Write_Device_Status (WDS).
- Service channel services (SVC) and realtime channel setup services (RTCS).
- Systems management interface: Services for hot-plug notification and network status management (e.g., Enable_Hotplug (EHP), Notify_Hotplug (NHP), Notify_Network_Status_Change (NNSC)).
- Error handling and phase switching: Enhanced mechanisms to support robust operation and controlled state transitions.
- Redundancy and hotplug improvements: Technical revisions to better support redundant topologies and dynamic device insertion/removal.
- Specification scope: Abstract service definition only - not a formal programming API. It can, however, be used as the basis for DL-Programming-Interfaces; implementation details (byte ordering, API correlation) are left to implementers.
- Conformance: There is no direct equipment conformance to this document; conformance is achieved through implementations of the corresponding data-link protocol that realize the Type 19 services.
Practical applications and who uses it
- Device manufacturers designing field devices and communication modules that must interoperate in time-critical industrial networks.
- Protocol designers and firmware developers implementing Type 19 data-link protocols.
- System integrators and automation engineers building deterministic control and safety systems where message timing, redundancy and hot-plug behaviour matter.
- Consultants and safety engineers specifying communication requirements for process and factory automation.
- Applicable in industries such as manufacturing, process control, robotics, and any automation context requiring deterministic fieldbus communications.
Related standards
- IEC 61158 series (Fieldbus specifications) - this part complements the three-layer fieldbus reference model in IEC 61158-1.
- IEC 61784-1 / IEC 61784-2 - for protocol type combinations and profiles that reference Type 19 implementations.
Keywords: IEC 61158-3-19, data-link layer, Type 19, fieldbus, industrial communication networks, time-critical messaging, hotplug, redundancy, phase switching, error handling, real-time communications.
Open preview (PDF)Industrial communication networks - Fieldbus specifications - Part 3-19: Data-link layer service definition - Type 19 elements
