Introduction to the selection and use of incremental rotary encoder

First, what are the key considerations when selecting an incremental rotary encoder? When choosing an encoder, there are three critical parameters to focus on:

1. Mechanical specifications, such as the size and positioning stops, shaft diameter, mounting hole locations, cable exit options, available installation space, and environmental protection levels. These must align with your application requirements.

2. Resolution, which refers to the number of pulses produced per revolution of the encoder. This should meet the precision demands of your design. The higher the resolution, the finer the measurement capability.

3. Electrical interfaces, as encoders often have various output modes like push-pull (F-type HTL format), voltage output (E), open collector (C, typically NPN-type transistor output, C2 being PNP-type), and long-line drivers. Ensure the output matches the input interface of your control system.

Secondly, how do we effectively utilize an incremental encoder? Here are some practical tips:

1. Incremental rotary encoders vary in resolution, measured by the number of pulses generated per revolution, ranging from 6 to over 5,400 pulses. Higher pulse counts mean greater resolution, which is a crucial factor in selection.

2. Incremental encoders typically provide three signal outputs (in differential six-signal form): A, B, and Z. These are generally at TTL levels. A pulses lead B pulses, and they are 90 degrees out of phase. A Z pulse is emitted once per revolution, serving as a reference for mechanical zeroing. Depending on the product, A may be forward and B backward, or vice versa—always check the manual.

3. If you're collecting data via a PLC, consider using a high-speed counting module. For industrial computers, a high-speed counting card works well. With MCUs, using an input port with an optocoupler is recommended for better noise immunity.

4. It's advisable to set B as the forward (positive) pulse, A as the reverse (negative) pulse, and Z as the origin-zero pulse. This configuration simplifies tracking direction and origin points.

In addition to these technical details, always ensure that the encoder is compatible with your existing equipment and environment. Regular maintenance checks can also help prolong the lifespan of the encoder, ensuring consistent performance over time. Proper handling during installation and operation is equally important to avoid damage to sensitive components. Whether you're using it for robotics, CNC machines, or other applications, an incremental encoder can greatly enhance positional accuracy and feedback control.