At left the convergent beam is used along with a pair of opposed mode
sensors in a bottle inspection application. The convergent beam is used
to determine that a cap is in fact present on the bottle. The opposed
pair determines whether the cap is on straight. Note that three bottles
are inspected. The number one bottle comes along, the convergent beam
sees a target, meaning the top is present. The opposed pair, in turn,
senses nothing, which means top is on straight. The second bottle comes
along, and the convergent beam detects nothing, meaning the top is absent.
At the last inspection, the convergent beam detects a target, meaning
the top is there, but the opposed beam is blocked, meaning the top is
on crooked. These types of applications are common. Note that the capacitive
switch from earlier slides could be part of the loop as well. While
the convergent sensor and the opposed pair work together to determine
that a cap is there and is properly placed, the capacitive switch could
at the same time inspect the bottles for fill or no-fill.
