How Rotary Encoder Works

At its core, a rotary encoder is a master of translation—it takes the physical motion of a rotating shaft and turns it into electrical signals that machines, computers, or control systems can understand. Think of it as a bilingual interpreter, bridging the gap between mechanical movement and digital communication. Let’s unpack this process, using examples from Shanghai Hengxiang Optical Electronics Co., Ltd.’s lineup to bring the mechanics to life.

Let’s start with the basics: most rotary encoders, including those from Hengxiang, rely on a few key components working in harmony. There’s the rotating shaft, which connects to the machinery (like a robot arm or a motor). Attached to this shaft is a code disk—a small, flat disk with patterns etched or printed onto it. Then there are stationary sensors (often light - based in optical encoders) and a light source, positioned to "read" the patterns on the disk as it spins. Finally, there’s circuitry that processes the signals from the sensors and turns them into usable data.

Optical encoders, a specialty of Hengxiang, are a great example of this synergy. Here’s how they operate: The code disk has alternating transparent and opaque segments, arranged in precise rings (or tracks). As the shaft spins, the disk rotates between a light source (usually an LED) and a photodetector (a light - sensitive sensor). When a transparent segment lines up with the light, the photodetector "sees" the light and sends a high - voltage signal (like a "yes" or "1"). When an opaque segment blocks the light, the signal drops to low voltage (a "no" or "0"). This rapid switching between high and low signals creates a stream of digital pulses, almost like a Morse code for motion.

But it’s not just about counting pulses—direction matters too. To determine if the shaft is spinning clockwise or counterclockwise, optical encoders use two separate tracks on the code disk, slightly offset from each other. Each track has its own photodetector. As the disk spins, the two detectors send pulses that are out of sync (a phenomenon called quadrature encoding). For instance, if detector A sends a pulse before detector B, the encoder knows the shaft is turning clockwise; if B leads A, it’s counterclockwise. This clever trick lets systems like Hengxiang’s incremental encoders track both speed (how fast the pulses arrive) and direction, making them invaluable for robotics or CNC machines that need precise movement control.

Absolute encoders, another key product from Hengxiang, take this a step further by tracking exact position, not just motion. Their code disks use a unique binary or Gray code pattern for every possible position—think of it as a unique barcode for each degree of rotation. Even if power is lost, the encoder remembers the last "barcode" it read, so when power returns, it knows exactly where the shaft is. This is critical for applications like medical scanners, where losing position data mid - procedure could be disastrous. Hengxiang’s absolute encoders achieve this with advanced code disk designs and onboard memory, ensuring no position is ever forgotten.

Magnetic encoders, though less common in Hengxiang’s portfolio, work on a similar principle but swap light for magnets. The code disk has alternating north and south poles, and the sensor detects changes in the magnetic field as the disk spins. While they’re more resistant to dust or moisture than optical encoders, they often trade some precision for that durability—making optical encoders the go - to for Hengxiang’s focus on high - accuracy applications.

No matter the type, the magic of a rotary encoder lies in its ability to turn messy, physical motion into clean, actionable data. Whether it’s an incremental encoder counting pulses to measure how far a robot arm has moved, or an absolute encoder reporting the exact angle of a wind turbine blade, the goal is the same: to give machines a way to "feel" and "report" their own movement. For Shanghai Hengxiang Optical Electronics Co., Ltd., this means refining every detail—from the etched patterns on the code disk to the sensitivity of the photodetectors—so that this translation is always accurate, reliable, and fast enough to keep up with the demands of modern industry.

In short, a rotary encoder is a motion detective, turning spins and turns into stories that machines can understand. And in the hands of experts like Hengxiang, those stories are always clear, precise, and ready to drive the next generation of automated systems.