Industrial Ethernet - integrating different protocols for machines by FPGAs from Softing
Various field buses for machines require time-consuming engineering and additional gateways. Field Programmable Gate Arrays (FPGAs) reduce substantially the expenses for machine-builders and equipment manufacturers to support the various communication protocols.
The problem: broad know-how, space requirement and costs
October 2nd, 2012 - The changing use of Industrial Ethernet field buses from machine to machine usually needs a broad know-how in handling the respective controller chips of the protocols and their specific hard and software interfaces. The support of the individual communication modules for the related protocols by the equipment manufacturers requires space and causes costs that can be avoided or reduced by an alternative.
Such an alternative for machine-builders and component providers consists of an embedded solution via FPGAs. This embedded solution has three main advantages, i.e.
- the reduced space requirement
- only one standardized software interface instead of a variety of protocols
- reduced number of hardware versions for the protocols.
Reduced space requirement of the FPGAs
The FPGA forms the communication interface that is integrated into the field device as an encapsulated IP component. For various communication protocols only the bus transceiver and the connection techniques are now to implement individually.
Only one standardized software interface instead of a variety of protocols
In the FPGA loadable IP cores are used containing both the communication controller, i.e. the hardware for the bus access, and the software stack for the protocol. The stack runs on a soft core processor, which is likewise loaded into the FPGA. So FPGAs use hardware and a software component.
For the encapsulation of the respective Industrial Ethernet implementation into the FPGA, Softing uses a standardized and slim software interface, which can be simply used (Simple Device Application Interface).
This software interface integrates all supported protocols for the data exchange with the device's application in such a way that all the protocol-specific program sections become unnecessary. The machine-builder or the equipment manufacturer does not have to deal with the details of the individual protocols. In fact, the machine-builder or the device provider uploads the application data into this communication interface. In such a way the application data has now become independent of the selected protocol.
So a standardized software interface covers the variety of the protocols enabling to focus on the application.
- Figure: Softing
Reduced number of hardware versions for the protocols
Since a FPGA can be charged with different IP cores, the number of hardware versions reduces. On top of that future extensions like the support of an isochronous protocol can be upgraded at any time even with designs already accomplished.
The most flexible implementation approach uses two processors in the FPGA (see figure).
The first processor executes the communication protocol, the second one the processing of the device's application. Alternatively the device's application for less complex field devices can be related to the same FPGA processor executing the communication protocol.
Finally a further implementation option applies the FPGA as a communication processor using a separate microprocessor for device's application outside of the FPGA.
More information about the flexible integration of Industrial Ethernet protocols into field devices.
Dipl.-Inform. Georg Suess
Product Marketing
Softing Industrial Automation GmbH, email georg.suess(at)softing.com
Softing Industrial Automation GmbH, Richard-Reitzner-Allee 6, 85540 Haar, Germany. Telephone +49(0)89-456-56-0, Fax +49(0)89-456-56-399, http://industrial.softing.com