Although the ubiquitous Mil-Std-1553 data bus is fast approaching middle age, data bus test, simulation and monitoring equipment boasts up-to-the-minute packaging and software. The new Airbus 380 avionics backbone is rapidly gathering similar support.
New 1553 simulation and test cards appearing on the market feature more bus channels, faster processors and even internal 1553 test buses. Many of the products are multiple-bus cards that process multiple protocols, saving space in test systems. Associated software provides integrated environments, more powerful analysis, improved graphics and even artificial intelligence (AI) features. As the military puts more emphasis on preventive maintenance, bus monitoring software may become a fixture in aircraft systems.
SBS Technologies (www.sbs.com), for example, is developing a flyable version of its PASS-3200 data bus analyzer, "embedded PASS," as part of a project to build a prototype high-capacity aircraft data acquisition and processing system. The system will store data in crash survivable memory and in removable memory for routine maintenance. SBS is part of a team, under the Universal Data Acquisition System (UDAS) program, led on the technical side by R-Net Engineering and Technology and including L-3 Communications, Electrodynamics Inc. and RLW Inc. The program is managed for the Air Force by Giordano Automation Corp.
Embedded PASS would function as a data collection and preliminary analysis tool, according to Lawrence Allen, SBS software manager. The idea is to provide a data acquisition and monitoring system that could be easily and inexpensively retrofitted into older aircraft. UDAS targets the F-16, but the F-15 and Joint Primary Aircraft Training System (JPATS) are also possible platforms.
On the F-16 the embedded SBS code would collect aircraft avionics data from the Mil-Std-1553 bus and approximately 100 other inputs from discrete and analog lines. SBS also will supply a flightworthy PC/104 1553 interface card. The onboard software would provide time-stamped data in engineering form that could be analyzed on board or downloaded to a notebook-based SBS ground station for immediate use or further analysis.
Multiple-Bus Boards
Ballard Technology (www.ballardtech.com) is introducing a new family of multiple-bus test cards, called OmniBus. The compact PCI (cPCI) version was expected to ship in late January, followed shortly by a PCI version. The company expects to release USB, VME and PCMCIA OmniBus cards by mid-2003, according to Kevin Christian, customer services manager.
The PCI and cPCI versions of OmniBus will feature two "cores," or protocol processing engines, and the VME cards, four cores. Each core can manage two independent, dual-redundant 1553 channels, or two independent ARINC 708 channels (for weather radar) or 16 independent ARINC 429 channels. Cards also can mix protocols. A PCI card, for example, can support 16 ARINC 429 channels and two ARINC 708 transmit/receive interfaces or 16 ARINC 429 channels and two dual-redundant 1553 interfaces. (I/O is added through 2-by-3-inch daughter cards.) Omnibus also implements IRIG-standard time stamps in and out for synchronization with other systems.
Excalibur Systems (www.mil-1553.com) also has launched a new line of Magic 4000 test card modules which allow users to mix and match 1553, 429, serial I/O, discretes and the H00-9 version of 1553 in a small footprint. The company expects to support ARINC 708 later in the first quarter. Magic 4000 includes PCI, cPCI, VME and VXI formats. The I/O modules can be used across all formats. On one PCI board, it is possible to implement four dual-redundant 1553 channels, or 40 ARINC 429 channels, or 16 serial I/O channels, or 60 discrete inputs and 20 discrete outputs, according to George Sponsler, Excalibur’s director of sales and marketing. One customer already has purchased a PCI board with one 1553 channel, five ARINC 429 channels, 15 input and five output discretes, and 12 serial channels. The company expects to add an Ethernet module in the second quarter of 2003, followed by Fibre Channel and Firewire (IEEE 1394) in the third quarter.
Enhanced Bit Rate 1553
Test cards for the 10-MHz version of the Mil-Std-1553, known as Enhanced Bit Rate 1553 (EBR-1553), are appearing, as well. Excalibur offers a single-channel EBR test and simulation card in both PC/104 and PC/104-Plus, the latter supporting the PCI bus. The company also plans to add an EBR-1553 card to the Magic 4000 family.
In January Data Device Corp. (www.ddc-web.com) was preparing to release a single-channel EBR-1553 PC/104 card, the BU-65580C1, for a deployed test system. DDC plans to add a channel of 1-MHz 1553, as well. Both Excalibur and DDC implement CANBus, which is used on EBR-1553 for serial remote terminal (RT) assignment. DDC has noticed an interest in the EBR module outside of the weapons community, which drove bus development, to extend the life of existing systems or bridge to faster buses, says Mike Hegarty, DDC’s product marketing manager.
DDC also has introduced a four-channel 1553 product, the BU-65566. The 66-MHz PCI mezzanine card (PMC) product is intended primarily as a flight card but also is usable in flight recorder test. The conduction-cooled unit includes RAM parity, autonomous bus controller (BC) architecture, autonomous built-in self-test and comes with free application programming interface (API) library software.
Software Upgrades
Ballard has released a new version of its CoPilot data bus analyzer, including ARINC 429, Mil-Std-1553 and ARINC 708. The software allows the creation of applications which convert from 429 to 1553 data and vice versa, supporting the needs of military aircraft with commercial avionics and government-owned corporate aircraft with military equipment. CoPilot also has added software and hardware playback features. Software playback allows technicians to replay recorded data through CoPilot filters to analyze timing, data values and relationships within the data. Hardware playback runs recorded data back to a box on the bench, so that the LRU responds as if it were on the airplane. A scripting engine also is provided for creating customized subapplications.
DDC has extended its 32-bit dataSIMS software to allow a more open interface. Users can easily import third-party controls and displays, such as instrument panels and gauges, Hegarty says. DataSIMS also now allows users to mix 1553 and 429 buses in one simulation and to add proprietary buses.
German data bus test specialist, AIM GmbH, has enhanced the scalability and openness of its bus analysis software, ParaView. Users, for example, can mix bus types, such as 1553 and STANAG 3910 (for Eurofighter projects) and avionics full duplex (AFDX) switched Ethernet and 429 (for Airbus 380 projects). The latest release illustrates the trend toward open systems, says Doug Ullah, director of sales and marketing. One feature is remote control of the interface from another application over an Ethernet network. Customers also can access AIM’s API to connect custom-written simulation models to the package. They also can access data from other data types and sources, such as RS 232 and RS 422 serial buses, and analog information. ParaView allows a "global" view of multiple bus types and parameters.
In January Excalibur was set to introduce Exalt, a new analysis tool that will support the Magic 4000 family, as well as other 1553 and 429 products. The first version of the Windows-based package will allow users to view discrete raw data, plot X/Y graphs in time correlation and look at averages of data, among other functions.
Montreal-based MAX Technologies’ (www.maxt.com) Maxim bus analyzer supports protocols such as ARINC 429/575, ARINC 561/568, ARINC 629, Async 422, and digital and analog I/O. Maxim version 1.0 includes graphics for message scheduling, recording, playback, monitoring and data analysis, with customizable controls, tool bars, fonts and colors.
On the hardware side, MAX Technologies provides an Industry Pack (IPack) module supporting Honeywell’s avionics standard communications bus (ASCB) for bus monitoring (four channels), user simulation (128 channels) and bus controller simulation. An ARINC 429 product in PCMCIA format provides four transmit and four receive channels with programmable error injection, receiver voltage thresholds and transmitter voltage and slew rate. The company also provides an IPack 1553 card, the IPM-1553-MRT, which implements two independent, dual-redundant bus channels. The product can simulate up to 31 remote terminals, one bus controller and one bus monitor per channel simultaneously.
Bus On Board
Condor Engineering’s (www.condoreng.com) new QPCI-1553 card fits not only four channels of 1553 logic but also full internal 1553 bus and transformer stub coupling for a unit under test (UUT) connection. Availability was expected in late January. The internal bus allows full built-in test of the card at the transceiver level, says Bill Schuh, manager of military avionics products. To ensure that the card’s transceivers are working, the channels can be switched to communicate with each other rather than with an external UUT. The checkout can proceed while the card is connected to a live, populated bus without disturbing the external bus. The new card doubles the channel count of its predecessor, the PCI-1553. Other solutions require an external bus, transformer coupler and terminators, Schuh says. The card also supports the ability to connect each channel directly to an external bus, through a stub coupler (external to the card).
The card can be used to compare actual and simulated remote terminal behavior. Simulated data from three new remote terminals (the bus terminals plus the LRUs) would be loaded into three of the four card channels. If no simulation was available for the bus controller, real BC data could be recorded from the actual 1553 bus and the file edited to remove the RT responses. The BC communications then could be loaded into the card’s fourth channel. To play the four data streams together through Condor’s BusTools data bus analyzer for RT response testing, the recorded traffic could be switched onto the card’s internal bus, simplifying setup. The results of this analysis can then be compared with prior analysis of the original LRUs to verify the performance of the new boxes.
Portable Terminal
National Hybrid (www.nationalhybrid.com) has introduced two four-channel 1553 boards, the PCI-format 15510 and the PXI-format 15520. These test and simulation products implement the equivalent of two dual-redundant 1553 buses, each emulating a bus controller with up to 31 independent remote terminals. Both cards can be used to simulate remote terminals on the bus in order to evaluate the bus controller or to simulate a bus controller "talking" to remote terminals/LRUs, in order to evaluate problems with LRUs or the bus. Customers purchasing the new cards receive Windows menu-based software, a C/C+ run-time library, "communication reconstructor" software to replay recorded message data for analysis, and parameter monitoring software.
The company’s four-channel, two-flight-terminal, 15503 data bus interface card, in PCI format, is intended to help develop software for NHI’s flight hardware. Flight Deck software is provided to "exercise" the terminals and simplify software coding and test.
The Personal Computer Enhanced Terminal (PCET), NHI-15164, a portable flight hardware terminal, plugs into a laptop printer port on one side and to a 1553 data bus on the other. The hand-sized unit makes the portable PC–loaded with FlightDeck software–into a 1553 simulator. The PCET also can be connected directly to the 1553 bus as a bus controller, remote terminal or bus monitor for test purposes.
ITCN (www.itcninc.com), a small company in Miamisburg, Ohio, has developed an "AI engine," as an adjunct to its SystemTrace hardware/software tool, which allows system-wide monitoring of multiple buses, backplanes and signal lines. ITCN is using the AI engine under an Air Force-sponsored project to predict LRU failures on the C-17 transport aircraft. First the software "learns" the normal behavior of the 1553 bus and then it monitors bus traffic to detect anomalies. The AI engine, in turn, would feed a software "prognostic engine," which would actually predict when the LRUs would fail. Currently ITCN is monitoring five of the C-17’s nine 1553 buses.
As an extension to this project, ITCN has proposed year-long, in-flight data monitoring of all nine C-17 buses. The idea is to collect failure trend data and associate it with specific box failures, permitting better failure prediction and preventive maintenance. (BIT typically indicates when a box is failing but not the anomalous behavior that led to the failure.)
Under a second Navy contract, the company is monitoring VME backplane traffic on P-3 patrol aircraft navigation and display computers. The project supports simulation, software development and system integration at the Maritime Surveillance Aircraft Facility, Patuxent River NAS, Md. The next step will be to fly the equipment in the same LRUs, to collect data for crew training, flight test and downstream diagnostics and prognostics.
Tech S.A.T., (www.techsat.com) like AIM, also supports the A380 AFDX bus. The company offers a PMC 694 module, based on a commercial, dual-channel Ethernet card. The product can be used on a PCI carrier or a VME processor card. Now the company is developing another dual-channel PMC AFDX test card, the AFDX-PM-2CTR, including features such as fault insertion/detection, time stamping, transmit scheduling and receive filtering. APIs are available under Linux and Windows.
The company’s AFDX line also scales up to a multiple-rack System Integration Bench (SIB)–based on the Avionics Development System 2 (ADS2). Tech S.A.T. is providing systems to Airbus in Germany to test, for example, LRUs associated with A380 cabin pressure and temperature, in-flight entertainment, and cabin intercommunication, video and audio.
Tech S.A.T also offers a portable unit called pAXAS (Portable AFDX Analyzer and Simulator). Used with a portable computer equipped with an AFDX PCM card on a PCI carrier, pAXAS provides a Windows/Linux-based graphical interface. Features include extended error injection and detection and filters, triggers, time stamps, scripting and dynamic parameter manipulation.
Beyond Cards and Codes
Mil-Std-1553 test is not limited to cards and code. UK-based BCF Designs (www.testbcf.com) offers a 1553 harness tester which isolates faults in the wiring of the bus, such as open circuits, short circuits, shorts-to-shield and crossovers. This helps test engineers to determine whether a problem is on a line replaceable unit (LRU) or on the bus. The S2476N Databus Network Tester simultaneously measures insertion loss.
Data Bus Products (www.databusproducts.com) produces a 1553 Bus Exchange Switch that allows users to switch in or out any unit under test (UUT) to or from any bus. In a lab or flight test environment, a box may have to be tested on multiple buses, reflecting the redundancy of onboard architectures. Engineers, for example, would want–before flight test–to analyze and resolve differences in a box’s behavior on different buses. The LabView software-controlled, high-capacity bus switch simplifies the setup involved in multiple-box, multiple-bus testing, where LRUs are not permitted to be removed from the aircraft. The 19-inch, rack-mounted configuration contains two rows of standard bulkhead jack connectors on the front side, with LEDs for identifying which buses are active. The switch allows the UUT to be put onto any or all of the aircraft or system buses without disconnecting and moving boxes and cables. Mil-Std-1553 input/output connectors are provided on the back side of the switch panel.