For count-based filling, a bottle containing fewer pieces than its specified fill count.
Also called: short count; bottle undercount; underfilled bottle.
What makes a count-filled bottle underfilled?
A bottle is underfilled by count when its verified piece count is below the specified target. Liquid level, unused headspace and individual tablet mass are different quantities.
A rejected bottle is not automatically a short-count bottle. The recorded reject reason and an independent contents check are different evidence. Separate counting, product inspection and physical rejection when interpreting the outcome.
Does a short-count bottle mean the counter undercounted?
Not necessarily. Separate the instrument’s indication from the actual count and from what was delivered to the bottle. A final short count alone cannot identify which stage caused the discrepancy.
In a simplified system that stops on the indicated target and delivers every detected piece to that bottle, an extra false counting event can produce a shortage. That is the opposite direction from “the sensor counted too few”. Real systems need evidence of their sensing, discharge and bottle-tracking sequence before this model can explain an observed shortage.
Can the total bottle weight prove its piece count?
Not by itself when individual piece weights vary. The same total product mass can represent different piece quantities. A weight signal and an independent piece count therefore provide different evidence.
An investigation should connect the verified bottle contents with the counter indication and the observed discharge and reject events.