Custom test bench design

As a test bench engineer, I design and deliver custom, turnkey test benches, from the tender response through to acceptance at the client's site.

A custom test bench, from specification to acceptance

A successful test bench starts with a well-defined need: what the bench must measure, how accurately, and above all how it will be used at the client's site. This work is done with the client, often as early as the tender response, alongside the sales team.

Next comes a complete architecture, covering software, electrical and mechanical design, conceived as a single system: a bench's difficulties almost always lie at the interfaces between these three disciplines. The project then continues with the teams and subcontractors through integration, validation on the bench and turnkey delivery, including documentation and training.

1. Gather the requirements and write the specification
2. Propose the software, electrical and mechanical architecture
3. Write the definition and design documents
4. Monitor suppliers, from order to acceptance
5. Integrate, validate on the bench and deliver, documentation included

What I take care of

• Software: control software on PLCs (CODESYS, NI RIO) and in Python, real-time development, LabVIEW HMIs and applications, post-processing in Python and Matlab.
• Electronics: electrical architecture, hardware selection, wiring of cabinets and harnesses, EtherCAT, CANopen and Modbus fieldbuses.
• Data acquisition: National Instruments (NI cDAQ, CompactRIO) and Dewesoft measurement chains, force, temperature and pressure sensors, cameras, measurement reliability checks.
• Mechanics: defining requirements and interfaces, managing subcontractors for design, manufacturing and pneumatic enclosures.

A multidisciplinary team

At STYREL's design office, a team of engineers, technicians and interns carries out the projects. My role as a technical manager: giving each person projects that match their skills and interests, building the schedule with the project managers, remaining the team's technical lead, and helping the team build its skills, project after project.

Some benches delivered

• Metrology benches for the ELT mirrorsSafran Reosc · zero-g support and positioning of 4.20 m, 3.5 t mirrors, M2/M3 interferometric bench, 1.50 m off-axis collimator.
• Ageing bench for the ELT bonded jointsSafran, via Intitek · a 4-month continuous test, 24 hours a day.
• Separation and compression testMaiaSpace · data acquisition and control system, pressure regulation.
• Filtration test systemEDF · redesign of the system used in nuclear power plants.
• Electrical test bench for sensorsAuxitrol Weston · testing of the temperature and pressure sensors it produces.
• Test facilitiesMBDA and SNCF · software support.

The technical choices behind a reliable bench

On every project, the aim is an architecture that the client's team can operate and maintain:

• Safety by design: every output is wired so that the absence of a command puts the bench in a safe state, even if communication is lost, and this is tested at acceptance.
• Configuration outside the code: measurement channels, thresholds and sequences are described in files, so the bench can evolve without recompiling. This is the subject of the article cRIO and WAGO over EtherCAT.
• Traceability: each result is recorded with the part tested, the bench configuration and the software version.
• The right tools for the client's team: LabVIEW, Python or both together, depending on what their teams can maintain. See Python and LabVIEW.

The full approach is described in the article Designing a test bench: mechanics, electronics and software.

See also: LabVIEW and National Instruments.