Custom Framework for Circuit Card Test Automation

Here is how our design addresses the issues presented by manually testing the BNC Front Panel circuit card:

• Sends automated tests through the test bench using custom test framework, reducing manual labour and saving time
• Detects circuit card failures before full system assembly saving many hours of troubleshooting and repairs
• Minimizes interactions between the user and live circuitry, decreasing potential exposure to high voltages
• Produces reliable and reproducible results with highly accurate automated testing
• Makes test setup and monitoring intuitive using a graphical user interface 
• Automatically generates test reports and organizes results
• Allows the user to test other devices in the future with custom tests which can be easily defined and modified

Software:

• Utilized Robot Framework test automation libraries to create reusable testing software extendable to any circuit card
  • Designed to be human readable and intuitive
  • Allows straightforward definition of new tests and manipulation of existing tests
• Integrated manual tests (such as visual checks) with automated tests for flexibility
• Implemented an automated excel test result report generator 
• Modular software design that allows for smart code reuse, and easy parallelization of work between the Test Framework and the BeagleBone server
• Low dependency between test framework tests and hardware
  • Requests tests from the server in a JSON format
  • Server runs test and sends the results as a JSON 
• Provided a simple interface for production staff to enter test metadata, start tests, and monitor tests
• Checked for proper signal definition using a programmatic suite validator

Hardware:

• Designed custom PCB for the hardware interface to condition the signals to be compatible with the BNC Card

• Utilized the BeagleBone Black development board as the core module of the board to handle computer to hardware communication
  • Substantial number of pins available for digital and analog signal definition
  • Accommodates communication with additional external peripherals if needed
  • Reusable for design of future hardware interfaces

• Designed and assembled custom mounting plates and panels for the test setup

• Our framework and hardware interface will be used by SKF to validate their BNC cards during production
• The G5 controller product line only requires small batch testing which makes it suitable for test set up that contains both automated and manual aspects
• SKF will be able to further develop our design in-house, reducing external cost requirements
• The design was made iteratively with constant feedback from sponsors and testing with production staff to ensure the solution best meets SKF’s needs
• Our framework is highly abstracted and intuitive, making it easy to extend to other circuit cards
• Our design is well-documented and detailed for successful handover to SKF

We validated our design solution by creating detailed test plans to verify our design at each major milestone. Prior to validation, we held internal design reviews among our team, and held external reviews with our sponsor to ensure we met their requirements and schedule. Our software was tested extensively when new features were added to ensure compatibility with the system. Our hardware design was thoroughly reviewed by our sponsor, and we additionally created and executed a detailed test plan to ensure the assembled hardware functioned correctly.

Software:

• Verified all BeagleBone input and output pins could be controlled and read via computer commands prior to any hardware integration
• Performed incremental code reviews facilitated by Git revision control to ensure code changes functioned correctly prior to system integration
• Developed programmatic validator to ensure signal definitions were correct before generating any signals on the hardware interface
  

Hardware:

• Created a detailed design specification to ensure all design decisions were logical and appropriate for our solution
• Validated our PCB schematic, layout, and component libraries using SKF procedures and checklists
• Verified correct component placement and values during PCB assembly, and conducted a full physical inspection after completion
• Performed continuity checks on critical signal paths to ensure correct connections

Integration Testing:

• Supplied controlled inputs to the hardware interface to validate specific signal paths
• Incrementally integrated software and hardware components to ensure no signals were misconfigured before full system validation

Key factors that made our design solution feasible were:

• Using the existing input and output control libraries of the Beaglebone board along with peripheral control libraries
• Using hardware components that did not require complex control signals
• Prior experience with Robot Framework on the software team
• Planning and testing designs in advance of deadlines leaving extra time for refinement
• Allocating time to implement improvements on the minimum viable product allowing us to exceed design expectations
• Defining clear technical specifications for both hardware and software ensuring that all stakeholder expectations were met
• Limiting the scope of our design to test a single unique circuit card creating more time for our software framework
• Regular support and feedback of 2 senior electrical engineers from SKF