P-Net
Profinet device stack for embedded systems
Web resources
Key features
-
Profinet v2.43
- Conformance Class A and B
- Real Time Class 1
- Multiple Ethernet ports
-
Easy to use
- Extensive documentation and instructions on how to get started.
- Build and run sample application on Raspberry Pi in 30 minutes.
-
Portable
- Written in C.
- Linux, RTOS or bare metal.
- Sources for supported port layers provided.
The RT-Labs Profinet stack p-net is used for Profinet device
implementations. It is easy to use and provides a small footprint. It
is especially well suited for embedded systems where resources are
limited and efficiency is crucial.
The stack is supplied with full sources including porting
layers and a sample application.
Also C++ (any version) is supported for application development.
The main requirement on the platform
is that it can send and receive raw Ethernet Layer 2 frames.
This software is dual-licensed, with GPL version 3 and a commercial license.
If you intend to use this stack in a commercial product, you likely need to
buy a license. See LICENSE.md for more details.
Getting started
See the tutorial in the documentation: https://docs.rt-labs.com/p-net/running_sample_app.html
Note that you need to include submodules when cloning:
git clone --recurse-submodules https://github.com/rtlabs-com/p-net.git
Features
- Multiple Ethernet ports (for Linux only, so far)
- TCP/IP
- LLDP
- SNMP
- RT (real-time)
- Address resolution
- Parameterization
- Process IO data exchange
- Alarm handling
- Configurable number of modules and sub-modules
- Bare-metal or OS
- Porting layer provided
- Supports I&M0 - I&M4. The I&M data is supported for the device, but not for
individual modules.
- Shared device (connection to multiple controllers)
Limitations
- This is a device stack, which means that the IO-controller/master/PLC side is
not supported.
- No media redundancy (No MRP support)
- Legacy startup mode is not fully implemented
- No support for RT_CLASS_UDP
- No support for DHCP
- No fast start-up
- No MC multicast device-to-device
- No support for shared inputs
- Supports only full connections, not the limited “DeviceAccess” connection type.
- No iPar (parameter server) support
- No support for time synchronization
- No UDP frames at alarm (just the default alarm mechanism is implemented)
- No ProfiDrive or ProfiSafe profiles.
Requirements
The platform must be able to send and receive raw Ethernet Layer 2 frames,
and the Ethernet driver must be able to handle full size frames. It
should also avoid copying data, for performance reasons.
For Linux:
- gcc 4.6 or later
- See the “Real-time properties of Linux” page in the documentation on how to
improve Linux timing
For rt-kernel:
- Workbench 2020.1 or later
An example of microcontroller we have been using is the Infineon XMC4800,
which has an ARM Cortex-M4 running at 144 MHz, with 2 MB Flash and 352 kB RAM.
It runs rt-kernel, and we have tested it with 9 Profinet slots each
having 8 digital inputs and 8 digital outputs (one bit each). The values are
sent and received each millisecond (PLC watchdog setting 3 ms).
Dependencies
Some of the platform-dependent parts are located in the OSAL repository and the
cmake-tools repository.
Those are downloaded automatically during install.
The p-net stack contains no third party components. Its external dependencies are:
- C-library
- An operating system (if used)
- For conformance class B you need an SNMP implementation. On Linux is
net-snmp (BSD License) used http://www.net-snmp.org
Tools used for building, testing and documentation (not shipped in the resulting binaries):
Contributions
Contributions are welcome. If you want to contribute you will need to
sign a Contributor License Agreement and send it to us either by
e-mail or by physical mail. More information is available
on https://rt-labs.com/contribution.
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