In X-Y positioning applications, such as automated pick-and-place, rotary encoders provide feedback on two axes of motion in order to determine X-Y coordinates. The encoder can be attached to the shaft of a ball screw or the drive motor of an actuator. In some cases a rack-and-pinion gear system or measuring wheel can be used to provide position information.
Shaft, thru-bore or measuring wheel encoders can be used in these applications, depending on the system.
Electrically, variables such as resolution, output type, channels, voltage, etc., can all be specified to meet the individual application requirements. Due to the reciprocating motion, since direction must be determined, choose an encoder that offers quadrature. Additionally, you'll need to specify an index pulse to ensure the ability to find a home position. Both incremental and absolute encoders are suitable for X-Y positioning.
Environmental considerations are important when specifying your encoder. Take into account the encoder's exposure to liquids, fine particulates, extreme temperatures, and washdown requirements. An IP66 or IP67 seal protects against moisture ingress, while a stainless steel or polymer composite housing to mitigate the effects of harsh cleaning chemicals and solvents.
Examples of Motion Feedback in X-Y Positioning
- Pick and place packaging robots
- SMT (surface mount technology) machines
- Automated microbiology testing machines
