Saturday, December 1, 2012
Product Focus: Databus Technology
0perators and manufacturers look for more capable and efficient alternatives to tried-and-true Mil-Std-1553 and ARINC 429 databus technologies
Fundamental technology change usually comes about at a very deliberate pace in the aircraft industry. This is especially true when it comes to the databuses that help run critical operations onboard civil and military platforms. Having proven themselves over decades, ARINC 429 and Mil-Std-1553-based technologies still enjoy a great deal of support despite their limitations. However, a transition is underway: operators and manufacturers are seeking more capable and efficient alternatives even as standards are being crafted to support higher performance, the integration of new technologies and increased safety.
“Even though it has been around for many decades, we are seeing ARINC 429 still growing at a really good rate,” said George Noh, director of sales and marketing at Holt Integrated Circuits, based in Mission Viejo, Calif.
Meanwhile, veteran military Mil-Std-1553 technologies are attracting commercial customers, such as the Airbus A350 and China’s COMAC C919.
“When it comes to … safety or time-critical data transfers … these old standards still have a lot going for them in terms of their deterministic nature and inherent reliability, which is why I think people have been so reluctant to move away from them,” said David Mead, Holt’s executive vice president and chief operating officer.
Then there is their huge installed base. “There is a lot of money out there (invested) in ARINC 429 systems, (for example) so you can’t flush them overnight,” added Bill Schuh, vice president of sales at Ballard Technology, of Everett, Wash. Since operators already have them, it is less expensive to keep them than “buying some of the newer ones.”
While there may be some reluctance to move on, the industry and technology developers are crafting strategies and technologies to replace or at least address the glaring shortcomings of these older systems, namely the relatively slow data speed rates, cost concerns and size, weight and power use (SWaP) issues.
On one front, developers delivering smaller, more versatile and lower cost commercial-off-the-shelf (COTS) products. “Traditionally, the ARINC 429 and Mil-Std-1553 (products) have been built using … military hybrid style technique, which has driven the high cost and the large footprint of these components,” said Mead.
To cut down the size, “we try to reduce BOMS (bill of materials), so that there are fewer parts (and) less of a footprint basically on the board,” said Noh. “We do that (in) many different ways, such as (using) DC-to-DC converters, which basically simplify all the power lines on the board.” This design approach is exemplified by Holt’s HI-3593 ARINC 429 terminal IC, which integrates “the protocol logic, the line drive, a DC-to-DC converter … into a single chip,” said Mead. “Everything runs from (an efficient) single 3.3 volt supply.” Holt also offers its HI-2130, which the company says is the industry’s smallest footprint for a Mil-Std-1553 terminal.
“We consider these COTS products,” said Mead. “They are not really application specific … (and) can essentially drop into their systems which makes it much easier to certify … with the FAA (and) are considered simple components as opposed to complex, so DO-254
certification becomes much easier (to accomplish).”
COTS products also “offer customers additional features that they might not have thought of,” said Schuh. “You can (include) multiple type functionalities: we even have a card that can have four or five different protocols operating simultaneously.” Ballard’s AB2000 BusBox product is just such a versatile product offering interfaces for Ethernet, USB and other I/O, and PMC expansion, Schuh said. Ballard is working on a program in which it will replace seven different line replaceable units (LRU) with one of its AB3000, a 5 x 5 x 2.5 inch device that can contain 12 1553 channels. The elimination of those boxes represents a significant space and weight savings, said Schuh.
GE Intelligent Platforms, based in Charlottesville, Va., “is offering XMC dual protocol card that provides 4 channels of Mil-Std-1553 and programmable ARINC 429 protocols,” said Benton Daniel, leader of the avionics business unit at GE Intelligent Platforms. Tapped for a key mission computer developed for a widely used rotary aircraft, the “card has provided our customer and the U.S. government with a substantial cost savings by migrating a complex design to a simpler and easier maintainable one by using a single card.”
For its part, Data Device Corp. (DDC) offers small form factor Mini-PCIe and USB boards that provide up to two dual redundant Mil-Std-1553 channels for any small embedded system, such as a laptop or tablet computer. “The USB style interface gives you flexibility to … move the board around because you are using a cable connection back to the computer,” said Sean Sleicher, marketing manager for data bus products with DDC, based in Bohemia, N.Y. The company also introduced in August a new databus interface card that offers up to 36 transmit/receive ARINC 429 channels.
To address data rate issues at least for the 1553 data buses, Edgewater Computer Systems of Ottawa is pressing ahead with development of its Extended 1553 (E1553) databus. “Depending on the network that it is going into,” it will typically yield anywhere “from 70 to 100 Mbps of physical rate throughput,” said Greg Fielding, Edgewater vice president of marketing. This is a significant increase over the 1 to 2 Mbps of traditional 1553 technologies. Currently in a PMC card form, E1553 was last year validated on three separate LRUs from different contractors on the BAE Systems Hawk in the U.K. Ministry of Defense program, and is currently being integrated in the flight management display of the CH146 Griffon to provide additional video capability to helicopter cockpit under a Canadian government-sponsored program.
Over the next year or two, the company is looking to take the technology to very small chip set and get the technology standardized as a Standardization Agreement (STANAG). The latter “should be ratified if everything goes well next summer, which is very important from a procurement standpoint, said Fielding.
However, many in industry are looking beyond the older technology protocols to Ethernet and optical solutions to boost capability and address SWaP issues.
“We are seeing things like (operators using) different Ethernet variants as the high speed backbone within the aircraft,” while still relying ARINC 429 and Mil-Std-1553 at “the sensor and actuator level,” said Mead.
“A good example of the continuing use of ARINC 429 is the flight entertainment network on the Airbus 380, where the 429 interface remains, but a simpler and readily maintained network protocol like Ethernet is used to move the data,” said GE’s Daniel.
The Avionics Full-Duplex Switched Ethernet (AFDX) or ARINC 664 part 7, which is used on the A380, “is in use primarily in commercial aircraft … but is making some inroads onto military aircraft, for example the F-16,” said Daniel.
Designed for safety critical applications, AFDX, which is based on IEEE 802.3 Ethernet technology and uses COTS components, “will continue to grow and replace older standards like ARINC 429 (because) it provides greater bandwidth, much faster speeds, and less weight and number of cables for aircraft designers to deal with,” said Daniel.
“A high-speed deterministic network is the core of an integrated system. It influences how efficiently we can integrate and align different functions,” said Mirko Jakovljevic, marketing manager at TTTech, based in Vienna, Austria. “Ethernet enjoys tremendous success in a variety of commercial and industrial applications, but it has limitations as a deterministic communications interface when applied to critical embedded systems in the past.”
Some operators are opting to avoid the cost and complexity of AFDX and using standard Ethernet technologies for systems that are not flight critical, said Schuh. In the case of flight critical systems “they are going to have something that is a little more robust, such as AFDX or even Time Triggered Ethernet (TTE). TTE and Time Triggered Protocol (TTP) have not been widely accepted into avionics backbones, but are being embedded into internal communications of LRUs and some flight controls.
“TTE certainly has some potential; there are some attractive features (associated with) having a deterministic Ethernet — particularly I can see the military embracing it,” said Sleicher. However, right now “we are seeing … the need for a lot of protocol conversion or bridging.”
With many older platforms adding new capabilities, there is a growing requirement to convert the legacy interfaces on these aircraft to work with the newer interfaces. To boost these link ups, DDC introduced this year its AceXtreme Bridge Device multi-IO converter that has two channels of 1553, 2 gigabit Ethernet ports and up to six programmable ARINC 429 channels. A small form factor box, it is available in a lab or rugged flyable version.
Meanwhile, Alta Data Technologies offers protocol translators — the eNet-1553 and the recently released eNet-429 — to bridge the gap between different standards.
“Our 1553 Ethernet product is a real time appliance,” said Harry Wild, vice president of sales of Rio Rancho, N.M.-based Alta Data Technologies. “It is like communications to a PCR or PCR express card, except you do it over UDP … (allowing) you to do is mix your technologies,” he said.
“Once you get everything in the same domain … you (can) take something like WireShark and look at all the data time synchronized together without having to record or play back the products the different components,” said Wild. Meanwhile, the company’s eNet-429 is a small, low-power, rugged device that connects the Ethernet with ARINC 429/575/573/717 Channels.
Aside from the Ethernet, controller area network (CAN bus) “has made some small inroads into the marketplace,” said Daniel.
A data bus protocol that has proven its reliability more than two decades in the automotive industry, “it is on virtually every aircraft that has come out in the last 15 years” handling non-critical tasks “like opening doors and maybe even running coffee pots,” said Schuh. “They still need an interface to it, and I get regular requests for CAN bus so that is something that is continue its usage in the industry.”
It’s not surprising the avionics community has expressed interest in CAN databuses, experts said, given its proven COTS background.
“Unlike ARINC 429 that is one transmitter multiple receiver multiple bus architecture, CAN is a shared media multi-drop bus architecture, so … it is a lot less wiring intensive … and can at run at up to 1 Mbps which is 10 times the ARINC data rate,” said Anthony Murray, Holt’s director of business development. Holt’s HI-3200 is designed to bridge multiple ARINC 429 busses and CAN bus.
“We are seeing higher and higher channel counts of CAN bus on commercial aircraft,” Sleicher added, noting there is an expansion port inside DDC’s AceXtreme Bridge Device that allows for an interface for CAN bus and additional 1553 and Ethernet or other ports, such as Serial IO.
There is also growing use of optical or fiber channel technologies on civil and military aircraft. The 1553 standard “is still reliable and robust, therefore, valuable for control systems, but not useful for data transfer, (and that) is really where the optical bus comes into its own handling video and the imaging” that require higher data rates, said Bob Hunt, head of engineering, RF2M Division, API Technologies, which developed the optical transceiver for the Typhoon Eurofighter. The opitical bus “goes back to 75 to 80 terminals on the aircraft … (and) operates at 20 Mbps,” he said, adding the data rate is already constraining the aircraft’s capabilities. “It covers the avionics, the munitions control and the communications within the aircraft,” he said. “There is a (1553) electrical bus that does run in conjunction with that (system) … for some of the controls.”
Hunt sees greater use of optical technologies “because it is protocol agnostic, and you can implement fairly traditional standard off the shelf technology and run whatever protocols you want through that technology.”
The company is developing and qualifying Opto Fire, an optical transceiver using the agnostic optical technology and targeted at a range of applications including aircraft, satellites and land vehicles, Hunt said. “It runs today at 2.5 Gbps per channel; since it is a four channel device, it is 10 Gbps on transmit (and) … on receive,” he said. The product is suited for new and retrofit applications. That technology is being developed with Vista, Calif.-based Ultra Communications.
Similarly, DDC is developing technologies for the High-Speed 1760 standard “that uses fiber channel as the interface and … a protocol (called) FC-AE-1553, (which) is a 1553-like protocol that runs on top of fiber channel at 1 Gbps,” said Sleicher. “High-speed 1760 is being used for weapons and storage management, launchers, and smart weapons,” but because it is similar to 1553 and offers an increase in speed and the number of nodes that can be on the network, “there is some potential there that could be used as a backbone type on an aircraft and helicopter.” Meanwhile, with the F-35s beginning to be delivered, there will be a growing need for testers for fiber channel systems used on those platforms, he said. DDC recently introduced its FC-75100 Series Fibre Channel Network Access Controller to address among other things this need.
Underlying these changes are key standards that are constantly being refined and updated. Currently, many developers are focused the efforts to address aircraft interface devices with regard to electronic flight bags (ARINC 834). The standard basically addresses “the software firewall between the
certified and noncertified avionics,” said Schuh. Ballard sits on this standard’s committee.
The proposed changes open up opportunities to the vendors. “Basically all the avionics standards that we work with are coming together into a single point in the cockpit to interface with Ethernet or whatever the backbone (is used), so that definitely lets us play in that area,” said Mead.
It could also provide guidance for vendors developing their own iPad type tablets, such a Alta Data, which working with North Andover, Mass.-based Network Allies to design a windows-based tablet with Mil-Std-1553 twinax lug connectors; “it has sold in so far to the v22 program,” said Wild.
More broadly, “increased safety and data assurance are becoming a standard requirement for aircraft manufacturers and avionics suppliers,” said Daniel. “Initiatives such as DO-178 for safety of onboard software, and Future Airborne Capability Environment (FACE) are driving avionics technology to higher performance, increased safety and more ease-of-use of components.”
“Based on ‘open architecture,’ without proprietary interfaces … FACE allows users to compete for portions of that architecture, said Daniel. “In this environment, anyone with the proper experience and knowledge can add products or create software applications.”
Next month: Cockpit Switches
Avionics Magazine’s Product Focus is a monthly feature that examines some of the latest trends in different market segments of the avionics industry. It does not represent a comprehensive survey of all companies and products in these markets. Avionics Product Focus Editor Ed McKenna can be contacted at firstname.lastname@example.org.
The following are new product announcements from databus manufacturers and suppliers.
▶ AIM GmbH, based in Freiburg, Germany, introduced a line of Ethernet based Mil-Std-1553 test and simulation products, the ANET1553 series. These boxes are based on AIM’s Common Core Architecture and provide the capability of running LINUX on board. The addition of a general purpose USB port allows additional capabilities such as data recording to removable media and wireless networking, the company said.
▶ In December 2011, Ballard Technology was acquired by Astronics Corp.
“Astronics is an excellent fit with Ballard’s culture and long term business strategy,” said Richard Steegstra, founder of Ballard Technology. “Being a part of the Astronics family presents complementary business opportunities and a potential for continued growth that will benefit Ballard’s customers, suppliers, and employees.”
▶ GE Intelligent Platforms introduced the R15-USB rugged Mil-Std-1553 module for portable deployment on-board aircraft, in ground stations and in testing facilities. It is designed or portable 1553 bus analysis applications that take advantage of the USB 2.0 form factor, the company said.
▶ Alta Data Technologies, of Rio Rancho, N.M., released eNet-A429, which provides real-time ARINC to Ethernet connectivity. Alta has designed a real-time FPGA “thin-server” UDP technology to provide direct packet access for ARINC-429/575/573/717 interfaces with automatic ARINC receive channel to Ethernet bridging.
Aero Express www.aeroexpress.com
AIM GmbH www.aim-online.com
Alta Data Technologies www.altadt.com
Avionica, Inc. www.avionica.com
Avionics Interface Technologies www.aviftech.com
Ballard Technology www.ballardtech.com
Beta Transformer Technology Corp. www.bttc-beta.com
Curtiss-Wright Controls www.cwcontrols.com
Data Bus Products www.databusproducts.com
Data Device Corp. www.ddc-web.com
Edgewater Computer Systems www.edgewater.ca
Elbit Systems www.elbitsystems-us.com
Emerson Connectivity https://emersonconnectivity.com
Excalibur Systems www.mil-1553.com
GE Intelligent Platforms www.ge-ip.com
Holt Integrated Circuits www.holtic.com
Hytronics Corp. www.hytronicscorp.com
MAX Technologies www.maxt.com
National Hybrid Inc. www.nationalhybrid.com
North Atlantic Industries www.naii.com
North Hills Signal Processing www.northhills-sp.com
Phoenix Logistics www.phxlogistics.com
Raycom Electronics www.raycomelectronics.com
Sanmina-SCI Technology www.sanmina-sci.com
Sital Technology www.sitaltech.com
Tech SAT GmbH www.techsat.com
Teledyne LeCroy Corp. http://teledynelecroy.com/
Tepro of Florida www.tepro-vamistor.com
Ultra Electronics www.ultra-electrics.com
Vector GmbH www.vector.com
Western Avionics Ltd. www.western-av.com
YED USA www.yed.com