FPGAs and the Industrial Ethernet Maze

Today, there are more than 25 Ethernet-based industrial communication systems that co-exist in the market. Vendors of industrial devices need to create solutions to optimally support multiple RTE (real-time Ethernet) protocols within a single hardware platform, and that can be field-upgraded to support new versions of existing protocols, or even completely different protocols, without replacing...

02/01/2009


Today, there are more than 25 Ethernet-based industrial communication systems that co-exist in the market. Vendors of industrial devices need to create solutions to optimally support multiple RTE (real-time Ethernet) protocols within a single hardware platform, and that can be field-upgraded to support new versions of existing protocols, or even completely different protocols, without replacing hardware.

An FPGA-based system supporting both RTE and standard TCP/IP

An FPGA-based system supporting both RTE and standard TCP/IP

Industrial Ethernet (IE) product developers combine the ubiquitous Ethernet physical layer with other hardware or software to create a “proprietary” or specialized RTE protocol, such as EtherCAT, EtherNet/IP, and Profinet. The objective is to add a real time and deterministic communication capability while retaining the advantages, popularity, and openness of Ethernet.

This type of universal access point can simultaneously serve I/O data communication, parameterization, configuration, diagnosis, and other applications. The ideal IE interface simultaneously supports standard protocols like HTTP and FTP in addition to industry specific RTE protocols to ensure scalability and flexibility. The main difference between “standard” and RTE protocols is that RTE protocols have a clear specification for deterministic communication.

FPGA-based solution

Field programmable gate arrays (FPGAs) represent an elegant solution to this problem. When combined with intellectual property (IP) cores for Ethernet, RTE protocols, and other industrial network standards, FPGAs enable designers to implement a single-board design that can support any of these communication standards. This not only reduces the form factor, but also saves time. Device manufacturers can cost effectively add industry standard networking capabilities to their automation products while retaining design flexibility in their systems due to FPGAs’ reprogrammability.

The creation of FPGA configurations is greatly accelerated by the use of pre-built IP cores that implement complex or specialized features, such as microprocessors or DSP functions. These IP cores are easily reused between different designs, different size FPGA devices, and even new generations of FPGA devices. Examples of IP cores include I/O interfaces (such as UARTs, PCI bus structures, or PWM circuits), processing functions such as FFT/FIR filters, or DSP functions, or more complex hardware functions like memory controllers and even microprocessors, such as Altera’s Nios II embedded processor, which is a high-performance 32-but RISC CPU.

When the product requirements change or the RTE protocol needs upgrading, a board redesign is not necessary. Instead, the reconfiguration requires only loading a new set of configuration data into the non-volatile memory. Circuit board design does not depend on proprietary (and sometimes expensive) ASICs that could become obsolete.

Design examples

One design example uses a Cyclone III FPGA (with 40K LEs) that contains MAC IP cores for RTE hardware support. The RTE could implement any of a range of available protocols. The “FPGA-based system” graphic includes an Ethernet switch with two external ports and one internal port, which enables the RTE device to operate in a daisy-chain topology. The internal port is used to exchange data between the embedded processor and the switch via a first-in, first-out (FIFO) buffer. A second embedded CPU is optional and could be used to run an application program.

It is vital to match a high-quality hardware design with a high-performance operating system (OS), otherwise the software will limit system performance. A designer can choose from a number of operating systems available for the embedded processor. For this discussion,μC-Linux and eCos are relevant choices. Both are available free-of-charge and include a broad community of support. Although a lightweight operating system, eCos includes support for all essential IP applications, such as simple network management protocol (SNMP). Another OS, μC-Linux, offers native support for a wide range of applications and protocols, but requires significantly more resources.

Integration Model 1: all hardware designed by the developer

In this model, the device manufacturer develops the hardware design that will be programmed into an FPGA. This approach is especially effective if the device application requires the integration of additional IP cores that contain vendor or application-specific functionality (such as for drive control).

Designers often use an evaluation-board kit, such as the MercuryCode evaluation board from EBV, as a starting point for evaluating and prototyping FPGA-based technology. The kit consists of an evaluation board with all the required development environments for both hardware and software. Generally, all appropriate operating systems and RTE protocols are available as evaluation and licensed IP cores to run on the evaluation platform. Embedded system developers use such kits for IP core evaluation, interoperability testing, and integrating prototypes into a target device.

Integration Model 2: vendor-supplied RTE module

Using a software vendor’s pre-designed communication module is a second alternative for developing lower-volume products, when developer bandwidth is insufficient, or when lead time is too short to design an RTE interface module from scratch. If custom FPGA design features are not required, incorporating a pre-built design integration package that effectively delivers an off-the-shelf, fully-functional RTE Module (RTEM) with a pre-installed hardware-configuration, protocol software, and operating system can free up scarce developer resources. The communication module is delivered with a complete development environment for creation of device-specific routines necessary for seamless device integration.

There are two main options for the physical device integration: direct integration of the RTEM as supplied, or asking the vendor to perform re-design an off-the-shelf communication module to meet specific customer requirements.

Combining solutions

The flexibility of an FPGA-based communications module is demonstrated by a design that runs standard applications using TCP/IP simultaneously with various RTE protocols. To achieve this task, simply use another embedded processor to support all the standard communication protocols (such as by using the

This design incorporates a switch component with two internal Ethernet ports, each with individual Ethernet address. As a result, a product developer can design a field device that offers two IP addresses (one for RT and one for IT traffic) to permit the independent and simultaneous support of, for example, a remote maintenance application and a real-time control application.

FPGAs now offer a realistic alternative to using ASICs at comparable (or even better) price, performance, and power consumption rates. For complex and evolving applications, where built-in flexibility and long lifetimes are a must, FPGAs provide the ideal solution without the additional overhead in cost, performance, or development time.


Author Information

Frank Iwanitz is product manager for real-time Ethernet at Softing AG. Stefano Zammattio is a product manager at Altera Corp.




No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Leaders Under 40 program features outstanding young people who are making a difference in manufacturing. View the 2013 Leaders here.
The new control room: It's got all the bells and whistles - and alarms, too; Remote maintenance; Specifying VFDs
2014 forecast issue: To serve and to manufacture - Veterans will bring skill and discipline to the plant floor if we can find a way to get them there.
2013 Top Plant: Lincoln Electric Company, Cleveland, Ohio
Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Plant Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.

Bring focus to PLC programming: 5 things to avoid in putting your system together; Managing the DCS upgrade; PLM upgrade: a step-by-step approach
Balancing the bagging triangle; PID tuning improves process efficiency; Standardizing control room HMIs
Commissioning electrical systems in mission critical facilities; Anticipating the Smart Grid; Mitigating arc flash hazards in medium-voltage switchgear; Comparing generator sizing software

Annual Salary Survey

Participate in the 2013 Salary Survey

In a year when manufacturing continued to lead the economic rebound, it makes sense that plant manager bonuses rebounded. Plant Engineering’s annual Salary Survey shows both wages and bonuses rose in 2012 after a retreat the year before.

Average salary across all job titles for plant floor management rose 3.5% to $95,446, and bonus compensation jumped to $15,162, a 4.2% increase from the 2010 level and double the 2011 total, which showed a sharp drop in bonus.

2012 Salary Survey Analysis

2012 Salary Survey Results

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.