PROFINET for Siemens
Real-time Industrial Ethernet standard by PROFIBUS International. Primary protocol for Siemens automation systems.
Protocol Overview
PROFINET is Siemens' native protocol. S7-1200/1500 have integrated PROFINET controllers. TIA Portal provides Hardware Configuration for graphical device setup with GSD file import.
When to Use PROFINET
Choose PROFINET for Siemens-based systems, high-performance applications, motion control, or when real-time deterministic communication is critical.
Siemens Hardware Requirements
Compatible Communication Modules
Integrated PROFINET interface (all S7-1200/1500)CP 1616/1626 (PC PROFINET interface)Scalance X switches (RT/IRT support)PROFINET I/O devices (ET200SP, ET200MP)Wiring Details
Network Setup
100Mbps/1Gbps Ethernet. IRT requires Scalance switches with PROFINET support. Topology: line, star, ring.
Configuration
Import GSD files in TIA Portal. Drag devices from hardware catalog to network view. Auto-configure I/O addresses.
Siemens Software & Programming
Function Blocks & Instructions
Built-in I/O access (mapped automatically)PNIO_SEND/PNIO_RECVD_ACT_DP (activate/deactivate device)GET_IM_DATA (device identification)RDREC/WRREC (read/write records)Siemens Code Example
// Automatic I/O mapping // Input: %I0.0 from ET200SP DI module // Output: %Q0.0 to ET200SP DO module // Manual acyclic read: RDREC( REQ := TRUE, ID := 16#0100, // Hardware ID INDEX := 123, MLEN := 20, RECORD => ReadBuffer, => DONE => Done );
Siemens-Specific Implementation Notes
Native Siemens protocol with deepest integration. Supports IRT (Isochronous Real-Time) for motion control with 31.25μs cycle times. Automatic topology detection. Diagnostics integrated in TIA Portal. Supports PROFIsafe for safety I/O.
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
Industry Adoption
Supported Message Types
Cyclic dataAcyclic dataAlarmsDiagnosticsSupported PLC Brands
Protocol Comparisons
PROFINET vs Modbus RTU
Modbus RTU is simpler and cheaper; PROFINET is faster and more capable
View Detailed Comparison →PROFINET vs EtherNet/IP
Both are high-performance Industrial Ethernet; choice driven by vendor ecosystem (Siemens vs Rockwell)
View Detailed Comparison →PROFINET vs PROFIBUS
PROFINET is the modern Ethernet successor to PROFIBUS fieldbus
View Detailed Comparison →Alternative Protocols
- EtherNet/IP
- EtherCAT
- POWERLINK
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