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The FT toolset supports such types of onboard channels as MIL STD-1553B, ARINC 429, Fibre Channeland some other types used in modern RTA systems. Channel adapters are installed in the instrumental computerswhich execute the testing scripts.For every type of onboard channel, the FT toolset supports: preparation and sending of test data to the RTA system through onboard interface channels (both packingparameters into messages and composition of “raw” messages are supported);6A FAMILY OF TESTBENCHES TO SUPPORT TESTING OF REAL-TIME AVIONICS SYSTEMSreceiving data from the RTA system through the channels for subsequent analysis (both unpackingparameters from messages and access to “raw” messages are supported); monitoring of data exchange through the channels between RTA devices and processing of monitoringresults by the testing scripts.The FT toolset can be extended to support new types of onboard interfaces.

Testbenches based on the FT toolsetsupport testing of RTA systems during all activities mentioned in Table 1.The FT toolset supports distributed execution of tests on multiple-computer testbench configurations, which isnecessary for testing complex RTA systems with large number of interfaces. Instrumental computers of the FTtoolset-based testbenches operate in synchronized time and perform coordinated sending of test data and processingof RTA system’s responses.

Time synchronization is guaranteed by periodical sending of precise time signals from adedicated instrumental computer (synchronization master) to all other instrumental computers.For operation with high-speed channels, for instance Fibre Channel-based video channels, it is necessary to useperformance-optimized hardware. The FT toolset supports integration with customized signal simulation hardware(SSH) systems which are parts of the testbenches (an example of SSH system is provided in Section 6). SSH systemsoperate under control from the testing scripts running on the instrumental computers.The FT toolset supports both fully automatic execution of tests (including batch mode) and interactive testing.Interactive features include: generation of requests to the user, e.g. “yes/no” request necessary for visual confirmation of displayed datacorrectness, or request for text comments to the user’s positive or negative response; support for manual input of test data by the user during the testing process; support for manual selection of tests execution order by the user (needed e.g.

for debugging of RTAsystem’s software on the testbench).During every testing session, a testing log is generated which contains the completion status (success/failure) ofevery executed test, user’s responses to interactive requests, etc. The log is automatically processed to determinewhich requirements were successfully verified (binding between requirements and test cases is defined within thetesting script). During the testing process, the testing logs, values of test data and response data are displayed in theonline visualization tool which allows the user to track the testing progress.

Custom visualization formats aresupported, such as dials, sliders etc; plugin interface is provided for adding new custom views.The FT toolset also supports recording of user’s actions (such as entering of test data, responses to tests’ requests,altering the tests execution order) for later replay. The record and replay option is useful for debugging of interactivetesting scripts.To support development of testing scripts in advance, prior to actual availability of RTA system devices to be tested,the FT toolset implements: software simulated “virtual” onboard interfaces, including MIL STD-1553B and ARINC 429; execution of testing scripts in user input expectation mode, in which the tests request data input from theuser instead of receiving the data from the (unavailable) RTA system devices; this mode does not requiremodification of tests.The FT toolset supports development and execution of simulation models for the RTA devices, based on hardwarein-the-loop simulation technology described in [5].

Simulation models utilize the resources of instrumentalcomputers, e.g. onboard interface adapters, to imitate the data exchange of the simulated device through the onboardinterface channels. Simulation models of the RTA devices can be used for testing the reconfiguration features of theRTA system in case some of the devices participating in the reconfiguration procedures are not available inhardware.The hardware resources of an FT toolset-based testbench can be shared with monitoring tools from the “Channelanalyzer” family [4].

Concurrent operation of FT tools and monitoring tools in a common hardware/softwareenvironment allows to create a compact solution for testing and monitoring of an RTA system. Such solution can beused for onboard diagnostics of RTA systems (see Section 7).Tests development subsystem of the FT toolset supports automatic generation of tests’ interface parts from theonboard interfaces database. The database is filled for every version of the RTA system’s software and is used forinformational coupling of the devices within the RTA system [6].5.2 Test description language featuresTest description language (TDL) implemented in the FT toolset is intended for specification of RTA system testingscripts. The scripts written in TDL are executed on the instrumental computers and interact with RTA devicesthrough onboard interface channels.

Testing scripts also control the operation of SSH systems, including the dataexchange between these systems and the RTA system.7V.V. Balashov, M.V. Chistolinov, R.L. SmelianskyTDL is an extension of the C language and provides language features for describing the structure of the test set,binding of tests execution to physical time, control of data exchange through the onboard channels, and generalcontrol of the testing process.Basic TDL unit for test coupling is the test component (TC).

TC source code consists of a header and a body.TC header specifies: Set, structure and hierarchical naming of test cases; Correspondence between test cases and requirements to the RTA system; Set and types of interfaces to onboard channels through which communication with the RTA system isperformed during testing; Structure of data words and messages transferred and received through interfaces; Set and types of auxiliary variables (parameters) intended for data exchange between different TCs andbetween TC and SSH systems; Set of testing logs recorded by the TC.TC body specified testing scripts’ activity on: Preparing the test data; Sending the test data into channels; Receiving data from the RTA devices through channels and checking the tested conditions (access tochannel monitoring results is transparently provided to the tests); Direct control of channel adapters, including turning on/off, setting service flag values, fault injection; Interaction with the user during human-assisted (e.g.

visual) checking of tested conditions; Control for generation of testing logs.TDL provides following functionality for automatic checking of timing constraints on responses from the RTAdevices (i.e. for testing the RTA system’s real-time characteristics): Waiting for a specified duration and then checking the condition on received data; Waiting for the condition on received data to become true, until a specified timeout expires; Constantly checking that the condition on received data remains true during a specified duration.A TDL project may include several TCs, in particular intended for execution on different instrumental computers.Even if only one TC is used, it can access channel adapters located on different instrumental computers. It is usefulin case a single TC implements scripts for comprehensive testing of the RTA system or its subsystem through a largeset of interfaces attached to different instrumental computers.5.3 Software structure of the FT toolsetThe FT toolset software contains the following subsystems:1.

Tests development subsystem, which supports editing of TDL source code of testing scripts.2. Testbench configuration tools which support: Binding of TCs to instrumental computers; Binding of TC interfaces to onboard interface adapters within the instrumental computers; Specification of data links between tests and SSH systems; Specification of detail level for testing events recording.3.

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