Scan heads for open linear encoders can be made very small to fit tight machine spaces. Component-style construction and a separate interface board go along with miniaturization, as in this RGH34 read head from Renishaw Inc.

'Encoding' or converting angular position into electronic signals is the mission of rotary encoders. Ways to detect motion include mechanical (via brush contacts) or magnetic/inductive methods, but noncontact optical encoders comprise the most common feedback device used in industrial motion control.

Optical encoders are critical components in systems with rotating shafts or parts. Optical rotary encoders are the most widely used way to transform mechanical rotary motion into electrical signals.

At its core, automation is defined by control loops, but automated machine safety is more aptly described as an arrow. And that arrow’s sharp point is often an encoder that makes it possible for the control system to know where it is and how fast it’s moving. With that knowledge, the system can not only avoid trouble, but act appropriately when circumstances bring trouble to its door.