Commission from physical link to process evidence
Four technologies, four jobs
EtherNet/IP adapts the Common Industrial Protocol to standard Ethernet and IP transport. PROFINET exchanges cyclic I/O between an IO controller and IO devices while carrying acyclic configuration and diagnostics. Both can control remote I/O, drives and machine devices, but their object models, engineering files and commissioning tools differ.
IO-Link moves one level closer to the field device: each sensor or actuator has a point-to-point link to a master port. OPC UA moves in the other direction: its address space, types, methods, events and subscriptions give meaning to data exchanged between software and equipment.
Do not confuse reachability with operation
A successful ping proves only part of an IP path. It does not prove a controller owns the right device, the assembly or module map matches, the process-data length is correct, or the application has accepted the device state. Commissioning must progress from physical link through identity and configuration to live process behavior.
Capture the controller diagnostic, device identity, configuration revision, expected data map, live input change and commanded output response. That evidence is more useful than a screenshot showing every icon green.
Where each protocol belongs
Use the comparison as a routing decision. If the task is deterministic remote I/O in a Rockwell/CIP ecosystem, begin with EtherNet/IP. If it is controller-to-IO communication in a PROFINET engineering project, begin with PROFINET. If a smart sensor needs parameters and diagnostics over a standard three-wire connection, begin with IO-Link. If applications need structured, secure information across vendors and operating systems, begin with OPC UA.
- Control I/O: EtherNet/IP or PROFINET
- Smart sensor/actuator port: IO-Link
- Semantic information exchange: OPC UA
- Mixed plant: define boundaries and ownership instead of declaring one universal protocol
A protocol-neutral commissioning record
Every connection should have an owner, intended producer and consumer, expected update behavior, configuration artifact, identity check, normal-state evidence and failure-state evidence. Record what should happen when a cable is removed, a device is replaced or the data becomes stale.
The linked guides below add protocol-specific details. They are training references, not substitutes for the current device manuals, network design, security policy or safety validation.
Field record
Evidence checklist
Primary technical sources
Use these official sources and the exact device manual for production work. This guide teaches diagnostic structure; it does not authorize live work or replace site procedures.