Rockwell Automation Implementation

PROFINET for Rockwell Automation

PROFINET is an open Industrial Ethernet system maintained by PROFIBUS & PROFINET International (PI). It uses standard Ethernet alongside Real-Time (RT) communication, with Isochronous Real-Time (IRT) available on Conformance Class C devices for demanding synchronized applications.

Type: Industrial EthernetSpeed: 100 Mbps commonly; Gigabit options are specifiedReleased: 2001Organization: PROFIBUS & PROFINET International (PI)

Depends on the selected physical layer

Bandwidth

Controller and project dependent

Max Nodes

100 m per copper channel; fiber depends on type

Max Distance

Yes

Real-Time

Protocol Overview

Allen-Bradley uses PROFINET IO via 1756-ENBT/EN2T modules with PROFINET option. Requires GSD files for PROFINET devices. Studio 5000 Add-On Profile for configuration.

When to Use PROFINET

Choose PROFINET when the selected controllers and field devices support the required conformance class and profiles, and when cyclic I/O, diagnostics, topology, safety, drives, or synchronized motion are part of the system requirement.

Rockwell Automation Hardware Requirements

Compatible Communication Modules

1756-EN2T/1756-EN3T (ControlLogix with PROFINET)

1769-L30ERM/L33ERM (CompactLogix with PROFINET)

ProSoft PLX32-EIP-PNC (gateway)

Stratix switches (limited PROFINET support)

Wiring Details

Network Setup

100Mbps Ethernet. RT (Real-Time) supported, IRT not supported. Star or line topology via switches.

Configuration

Import EDS/GSD in Studio 5000. Add PROFINET devices to I/O Configuration tree. Map to controller tags.

Rockwell Automation Software & Programming

Function Blocks & Instructions

Automatic I/O tag mapping

MSG for acyclic data

ProSoft configuration via web interface (if using gateway)

Rockwell Automation Code Example

// PROFINET I/O device automatically mapped to controller tags:
Input_1 := Local:1:I.Data[0];  // PROFINET device input
Local:1:O.Data[0] := Output_1; // PROFINET device output

// Acyclic via MSG not commonly used for PROFINET

Rockwell Automation-Specific Implementation Notes

PROFINET support is not native - requires specific EN2T/EN3T modules or gateway. Limited to PROFINET IO (no component-based protocol). No IRT support. Primarily used in mixed Rockwell/Siemens installations.

Technical Specifications

Physical Layer

Physical Layer: IEEE 802.3 Ethernet
Cable Type: Cat5e/Cat6 Ethernet, fiber optic
Topology: Line, Star, Tree, Ring
Power Over Cable: No

Data Layer

Data Link: Real-Time (RT) and Isochronous Real-Time (IRT)
Encoding: Binary
Error Detection: CRC-32
Frame Size: 1500 bytes (MTU)

Performance

Scan Time: RT update times: 250 µs to 512 ms
Deterministic: Yes
Real-Time: Yes
Cycle Time: IRT can reach 31.25 µs on supported CC-C devices

Certification

Certification Required: Yes
License Cost: No PROFINET technology licence fee; product certification and testing still apply
Version: V2.4

Advantages & Disadvantages

Advantages

✓All conformance classes include real-time data exchange, alarms, diagnostics, and topology support
✓Conformance Class C adds IRT for synchronized applications
✓Standard Ethernet and PROFINET traffic can share a network when it is engineered correctly
✓Profiles such as PROFIsafe and PROFIdrive extend the base protocol for defined application needs
✓Copper, fiber, and other specified physical-layer options support different plant environments
✓PI certification provides an interoperability test path for products

Disadvantages

✗Capabilities vary by conformance class, optional feature, profile, and exact device
✗IRT requires compatible Conformance Class C hardware and an engineered network
✗Copper channels are limited to 100 m between endpoints without another active node
✗Device naming, GSDML files, topology, update times, and diagnostics all require commissioning discipline
✗Product certification and test-lab work add effort for device manufacturers

Common Use Cases & Applications

High-speed manufacturing lines

Motion control applications

Process automation

Automotive manufacturing

Robotics integration

Safety-critical applications

Adoption & Ecosystem Context

Adoption LevelEstablished global PI standard

Primary-source market sharePI does not publish a primary-source percentage

Geographic PresenceGlobal vendor and user ecosystem

Primary Industries

AutomotiveManufacturingProcess IndustriesPackagingMaterial Handling

Supported Message Types

Cyclic data

Acyclic data

Alarms

Diagnostics

Supported PLC Brands

Siemens ABB Schneider Electric

Phoenix Contact

Beckhoff Rockwell

Wago

Omron

Quick Links

Alternative Protocols

EtherNet/IP
EtherCAT
POWERLINK

Related Standards

IEC 61131-3
International standard for programmable logic controller programming languages. Defines 5 programmin...
IEC 61131 Series
Complete series of international standards for programmable logic controllers covering hardware, sof...
PackML
Packaging Machine Language - standard state machine and interface for packaging machinery. Part of I...