The Integration Challenge#
Robotics, multi-board assemblies, and sensor-heavy products create testing challenges that go beyond single-board validation. Motors need to move, sensors need stimulus, boards need to communicate, and the system needs to behave correctly as an integrated whole.
These integration challenges are real, but they create a temptation to overthink fixtures. Often the right approach is simpler than it appears: test boards individually with standard fixtures, then validate integration at the system level.
What Makes Complex Products Different#
Multi-board assemblies: Products with multiple PCBAs—main boards, daughter cards, sensor modules, power boards—need testing at both board and system levels. Each board has its own test requirements, and the assembly has integration requirements.
Motor and actuator systems: Robotics and motion products need to exercise motors, verify positioning, test limit switches, and validate control loops. Test fixtures need mechanical accommodation and often motion clearance.
Dense sensor arrays: Products with many sensors—environmental, position, force, optical—need comprehensive sensor validation. Each sensor type has different stimulus requirements and verification approaches.
Inter-board communication: Boards that communicate via I2C, SPI, CAN, or other buses need verification that communication works correctly across the assembly. This is system-level validation, often not practical at individual board test.
Power distribution: Complex products often have sophisticated power architectures—multiple rails, sequencing requirements, battery management. Power system validation is typically a system-level concern.
Test Strategy for Complex Products#
Complex products usually benefit from a layered test approach:
Board-level test: Each PCBA tested individually with standard fixtures. Catches manufacturing defects early, where they're cheapest to fix. Standard FixturFab fixtures handle this cleanly.
Module-level test: Sub-assemblies (sensor modules, motor assemblies, communication interfaces) tested as units. May use fixtures, jigs, or system-level test depending on module complexity.
System-level test: Complete product tested in assembled state. Validates integration, communication, motor function, sensor correlation. Often uses different test infrastructure than board-level fixtures.
Not every product needs all three levels. Simpler products can skip directly from board test to final system validation. Complex products often need intermediate validation to isolate problems efficiently.
The Fixture's Role#
For board-level testing of complex products, fixtures do exactly what they do for simpler boards: provide reliable electrical access to test points. The complexity lives elsewhere:
- Test software handles multi-board coordination and integration verification
- System-level fixtures or jigs accommodate mechanical complexity for integration testing
- Test architecture defines the handoffs between test stages
Standard FixturFab fixtures work for board-level testing of boards from complex products. The boards themselves are still PCBAs with test points—fixture requirements don't change just because the final product is complex.
Common Configurations#
Robotics and motion products: Board-level fixtures handle electronics testing. Motor and motion testing often requires separate mechanical test setups that accommodate movement, load testing, and positioning verification.
Multi-board assemblies: Each board gets its own fixture optimized for that board's test points. System-level testing may use cable assemblies connecting multiple boards in test configuration, or assembled-product test jigs.
Sensor-dense products: Fixtures provide electrical access to sensor interfaces. Sensor stimulus often requires additional test equipment or environmental control (temperature chambers, motion simulators, optical sources) beyond the fixture.
What We Recommend#
Test boards individually. Configure fixtures for each board in your assembly. This catches 80%+ of manufacturing defects at the earliest, cheapest detection point.
Keep fixtures simple. Resist the temptation to build system-level complexity into board fixtures. The fixture's job is electrical access—keep integration testing separate.
Use standard signal interfaces. Complex products have complex interfaces, but they're still built from standard building blocks: JTAG, I2C, power rails, analog signals. Standard signal interface options handle most requirements.
Plan system-level test separately. Integration testing may need mechanical jigs, cable harnesses, or test equipment that's different from board-level fixtures. That's fine—different test stages have different requirements.
Iterate based on defect data. Your initial test strategy is a hypothesis. Refine it based on actual defect data: where do problems occur, how are they detected, what escapes to later stages?
Custom Fixture Considerations#
Some complex products genuinely need custom fixture work:
- Unusual board geometries that don't fit standard base sizes
- Multi-board simultaneous test where testing boards together is necessary
- Mechanical integration where the fixture must accommodate non-standard product geometry
When custom work is warranted, we offer consultation and custom fixture development. But the first question is always whether standard fixtures can do the job—they often can, even for complex products.
Next Steps#
Start by identifying the PCBAs in your product and configuring fixtures for each in Studio. See how standard fixtures address your board-level test needs before evaluating custom requirements.
If you're facing integration testing challenges that go beyond board-level fixtures, contact us to discuss your system test architecture. We can help you identify where standard fixtures fit and where you might need different approaches.