The inherent precision within Scroller geometry means that nothing slips. Consequently the same point on the roller always lines up with the same point on the belt. This remarkable timing accuracy of the movement and belt to roller alignment allows:

• stops (gauge)
• marks (speed sensor)
• electrical contacts (switch)
• hole patterns and shapes create differing patterns and durations. (fluid control)

  Fig. 19

• bumps (dial)

  Fig. 20

  (Link: Geometry, syncro)
  (Link: Conditions)

Switch Contacts	Limited Travel Fig. 21a
Knob = Dial	Fig. 22

(Link: Geometry, syncro)