photoelectric register control

photoelectric register control

[¦fōd·ō·i′lek·trik ′rej·ə·stər kən‚trōl]
(control systems)
A register control using a light source, one or more phototubes, a suitable optical system, an amplifier, and a relay to actuate control equipment when a change occurs in the amount of light reflected from a moving surface due to register marks, dark areas of a design, or surface defects. Also known as photoelectric scanner.