A check using samples with known characteristics to assess a specified inspection response and, where included, the rejection response.
Also called: test sample; challenge sample; performance check.
Known samples and the function being tested
A challenge has a known reference characteristic and a defined function to exercise. For count-related inspection, that might be an independently established bottle count or a specified count defect. A displayed target count alone is not independent evidence of what the bottle contains.
Keep the reference condition, observed inspection decision and actual bottle outcome separate. Sensing, product feeding and bottle rejection are distinct functions; evidence for one should not silently stand for all three.
Does a metal-detector test validate tablet counting?
No. A metal test piece challenges metal detection under its defined conditions. Metal, X-ray, weighing and piece counting are different inspection tasks. A check that also exercises a metal detector’s reject device still does not establish bottle-count performance.
Match the challenge evidence to the question
Evidence described
Question it can address
Known count compared with a count result
Did this count assessment agree with the reference?
Known defect and an inspection decision
Did the specified inspection recognise this defect?
Reject command and physical feedback
Did the configured reject response occur?
Metal test-piece response
Did the specified metal-detection function respond?
Recording a counting challenge result
Record the function exercised, known sample condition, operating conditions and observed outcome. A short bottle assessed only at a downstream inspection challenges that inspection, rather than the upstream counter.
Detection and removal need their own observations when both are within scope. A defect alarm is not physical reject confirmation. Results from a limited set of challenges also should not be rewritten as a guarantee for every future bottle; miss rate and false reject rate ask different questions about known sample groups.