Rockwell Automation Implementation

PROFINET for Rockwell Automation

Real-time Industrial Ethernet standard by PROFIBUS International. Primary protocol for Siemens automation systems.

Type: Industrial EthernetSpeed: 100 Mbps / 1 GbpsReleased: 2001Organization: PROFIBUS & PROFINET International (PI)

1 Gbps

Bandwidth

256 per segment (thousands with routing)

Max Nodes

100m per segment

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 for Siemens-based systems, high-performance applications, motion control, or when real-time deterministic communication is critical.

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: 250μs to 32ms
Deterministic: Yes
Real-Time: Yes
Cycle Time: 31.25μs (IRT)

Certification

Certification Required: Yes
License Cost: Device certification required
Version: V2.4

Advantages & Disadvantages

Advantages

✓True real-time performance (IRT mode)
✓High speed and bandwidth
✓Extensive diagnostic capabilities
✓Hot-swapping devices
✓Integrated safety (PROFIsafe)
✓Large installed base
✓Support for motion control
✓Web-based management

Disadvantages

✗More complex than Modbus
✗Requires PROFINET-certified devices
✗Steeper learning curve
✗Higher initial cost
✗Requires managed switches for IRT
✗Siemens ecosystem bias

Common Use Cases & Applications

High-speed manufacturing lines

Motion control applications

Process automation

Automotive manufacturing

Robotics integration

Safety-critical applications

Industry Adoption

Adoption LevelVery High

Market Share35-40% of industrial Ethernet

Geographic PresenceWorldwide, strongest in Europe

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

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