Parallel testing creates several active unit contexts inside one station. A barcode that belongs to the first fixture position must remain attached to that board even if another socket finishes first. Validate this association independently of whether the electrical measurements pass.
NI’s guidance on setting unit serial numbers shows socket-indexed unit information in parallel and batch execution. That distinction matters whenever one station handles several boards concurrently.
Define the identity relationship
Give each physical fixture position an unambiguous operator label. Map that label to the software socket index, scanned unit identity, and current test attempt. Document any difference between zero-based software numbering and the labels printed on the fixture.
Do not use completion order as a substitute for socket identity. A slow measurement, retry, or operator action can change the order in which records arrive. The record should carry its association explicitly from scan through final storage. Display the physical position beside the identifier during loading so mistakes are visible early.
Use deliberately distinguishable validation units
Load boards or suitable test substitutes with different known identities. Introduce a controlled difference in execution time so they finish out of loading order. Confirm that every measurement, attachment, and final disposition remains associated with the intended position and unit.
| Scenario | Association to inspect |
|---|---|
| One socket empty | No inherited identity or phantom result |
| One socket interrupted | Other units retain their own state |
| Units finish out of order | Storage uses explicit unit context |
| One unit is reloaded | New attempt replaces only that position’s context |
Check shared interface boundaries
Inspect scanner input routing, operator dialogs, shared instrument callbacks, and report filenames. These are common places where a global “current serial number” can replace the correct per-socket value. Pass the unit context deliberately to asynchronous work rather than reading whichever value happens to be current later.
Make unloading and reloading rules explicit. A board must not acquire the preceding occupant’s identity because the new scan was omitted. Likewise, rescanning one position should not modify results already captured for another position.
Review the database or exported records as well as the station display. A correct display does not establish that the same identity reached storage, particularly when results are queued and written after execution.
The acceptance evidence is a set of intentionally varied parallel runs with verified associations. Electrical test validation and identity validation answer different questions; both are needed before results from several simultaneous boards can be trusted as individual production records.
Move from reading to a build-ready project
Use the fabrication and assembly checklists to prepare drawings, production files and test requirements.
Open the DFM checklist