Балашов et al eucass monitoring (2011) (Лекции 2014-2015), страница 2

Figure 1. Monitoring toolset structure

Resident module of the toolset runs on a recorder PC (REC PC) and includes:

• adapter drivers;

• monitoring agent responsible for interaction between user-controlled workstation module and adapter drivers.

REC PC includes channel adapters supporting sender/receiver/monitor functions (ARINC 429), bus controller/remote terminal(s)/bus monitor functions (MIL STD-1553B); for each channel type, the adapter may support one or several functions at once. Monitoring toolset is optimized for specific channel adapter cards produced by Elcus company and Space Research Institute, Russia.

Adapter drivers are built to enable multiple non-blocking access to adapters performing receive-only functions (channels monitors, ARINC 429 receivers), and independent (though blocking) use of remote terminals (RT) on multi-RT MIL STD-1553B adapters and of output channels on ARINC 429 channels with many such channels. This enables cooperative use of PCs and adapters by monitoring tools and by hardware-in-the-loop integration/testing toolset [1]. Drivers also perform pre-filtering of received data according to user-specified criteria in order to optimize traffic to workstation and recorded trace size (which is crucial for long-run recording). Simulation of MIL STD-1553B and ARINC 429 channels is implemented by specialized drivers of "virtual" channel adapters.

Monitoring agent, in addition to interaction support functions, supports execution of complex data exchange schedules, for instance those constructed by Scheduler CAD tool [13]. As adapter cards support end-to-end execution for single exchange chain only, the monitoring agent performs real-time reloading of exchange chains to bus controller cards.

Workstation module of the toolset runs on a workstation PC (WS PC). A single instance of this module running on a WS PC can control monitoring agents on several REC PCs. Workstation module includes:

• subsystem for recording of data received from agents, and for interaction with agents;

• subsystem for checking correctness of recorded data;

• user interface.

Data recording subsystem writes the received data to a hard disk (splitting them into chunks of specified duration) and reads the previously recorded data to be displayed in GUI. During online monitoring, data bypass the recording phase and are displayed in GUI in real time (writing to a disk is performed concurrently).

Data correctness checking subsystem supports on-the-fly testing of received data against correctness constraints, such as belonging to specified ranges, conformance to smoothness requirements, correlation of data values transferred through duplicated channels etc. Data correctness check is performed on parameter values unpacked from recorded messages; unpacking is performed according to message structure specification which is entered by the user or imported from the project database. There is also an option to check the recorded exchange sequence for conformance to a specified exchange schedule.

User interface represents the monitoring results in following forms:

• parameter-oriented views, displaying unpacked parameters in table and graph forms;

• exchange-oriented views:

  • exchange log;

  • exchange statistics (including error statistics), calculated for different addresses and subaddresses separately;

  • last recorded exchange for each sender-receiver pair (MIL STD-1553B) or word address (ARINC 429);

• user controls for operation with:

  • MIL STD-1553B bus controller and ARINC 429 data sender, including exchange schedule specification;

  • MIL STD-1553B remote terminals, including setting up and viewing data for subaddresses;

• tools for setting up filters for data recording and display;

• tools for data search.

Integration of workstation module of the toolset with project database is in progress. Database integration enables import of messages structure and exchange schedule specifications from the database.

In mobile installation of the toolset, workstation PC and recorder PC is the same computer (a rugged notebook).

4. Workflow for toolset application

In this section we describe the workflow for application of the presented monitoring toolset as a part of simulation-based integration workflow proposed in [1]. The workflow from [1] includes following steps:

1. filling the RTA system project database with data on the system structure, on protocols and formats of data exchange between devices;

2. automated generation of interface sections of the RTA system device models (including input and output parameters, interfaces of models with channels, interconnections between models);

3. implementation of the functionality logic for models of the devices that are not yet available in hardware, on one of the levels of detail:

   1. detailed implementation that includes source code of device’s software;

   2. simplified implementation, imitating external behaviour of the device;

4. automatic construction of schedules of data exchange for MIL STD-1553B channels (by means of Scheduler CAD);

5. automatic generation of code for schedule definition in the following formats:

   1. unified format for target devices and device models, recognizable by the code of system tasks running either on models or on real devices;

   2. specialized format for simplified models which do not contain code of system tasks;

6. automatic generation of code for message packing and unpacking in the following formats:

   1. unified format for target devices and device models;

   2. specialized format for simplified models;

7. integration of generated code into the models and available real RTA system devices;

8. preparation of the testbench hardware, in particular connecting instrumental computers and available RTA system devices to the data exchange channels;

9. defining the configuration of the testbench: distribution of models to instrumental computers, settings for channel monitoring and for registration of simulation events;

10. performing the simulation with a given set of hardware RTA system devices and device models;

11. analysis of simulation results, including automated verification of conformance of the recorded data exchange sequences to reference exchange schedules from the project database.

Monitoring toolset is involved at following steps:

• steps 1 and 4: input data for the toolset are entered into the project database;

• step 8: hardware (including REC PCs and adapters) is set up for use by resident module of the monitoring toolset;

• step 9: binding of “logical” channels to specific adapters on REC PCs is defined; data exchange specifications are loaded from the project database into the workstation module of the toolset;

• step 10: during simulation, the monitoring tools record and analyze the data exchange through real and simulated channels;

• step 11: the user performs offline analysis of monitoring results.

If there are no hardware devices available on the current stage of RTA system development, steps 7-11 involve only simulation models of the devices and constitute a process of “virtual” integration. During this process, real source code for the devices and real exchange schedules are validated via testbench and monitoring tools.

Application of monitoring toolset during in-field testing and operation of RTA system is generally the same, however on all steps involving monitoring toolset a real RTA system and a mobile monitoring solution are used. For in-field operation, step 10 may be long-lasting, and step 11 may require delivery of collected recording results to an engineering laboratory for analysis.

5. Case studies

Two industrial case studies for monitoring toolset application are considered below.

Stationary monitoring solution for integration/testing bench. In 2009, a testbench for integration and testing of aircraft RTA systems was created and accepted for operation. This testbench includes several instrumental computers equipped with MIL STD-1553B and ARINC 429 adapters, and workstations. Instrumental computers perform functional and integration testing activities under control from workstations, generating test data traffic and checking responses from RTA system devices. Instrumental computers are also capable of running simulation models of unavailable RTA system devices. Monitoring toolset's resident modules are installed on all instrumental computers, and onboard interface adapters are shared between testing and monitoring tools. Monitoring tools can be used either as a source of information on data exchange between RTA system devices and instrumental computers (e.g. for test or model debugging purposes), or as a standalone facility for generation of simple traffic for RTA system devices in course of development of devices' source code. In both cases, the online monitoring functions are mostly used. The testbench is connected to a server which hosts the project database to enable automatic import of data from the database.

Mobile monitoring solution for in-field testing. This solution is currently under development. It is based on a rugged notebook with several USB-attached MIL STD-1553B adapters and intended for long-run recording of data exchange for naval RTA systems. The focus is on detecting exchange errors and deviation of transferred parameter values from given specifications. The user performs mainly offline analysis activities.

6. Conclusion

In this paper we presented a toolset for monitoring of data exchange on MIL STD-1553B and ARINC 429 channels in real-time avionics systems. This toolset supports different phases of simulation-based RTA system development process proposed in [1]. Two industrial case studies of toolset application were considered.

Directions for future development of the monitoring toolset include:

• completion and delivery for operation of the mobile monitoring solution;

• development of monitoring solution for high-speed Fibre Channel bus;

• development of scripting subsystem for specification of user-defined constraints on correctness of transferred data.

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