By disk encoder technology classification

Incremental encoder

Incremental Encoder Diagram

Operation Principle: Incremental encoders directly utilize the photoelectric conversion principle to output three sets of square wave pulses A, B, and Z; the A and B pulses are 90 degrees out of phase, which facilitates the determination of the rotation direction. The Z pulse occurs once per revolution and is used for reference point positioning.

Features: The advantages include a simple principle and construction, mechanical average lifespan of over 10,000 hours, strong anti-interference capability, and high reliability, making it suitable for long-distance transmission. The drawback is that power interruption will result in loss of position information. Additionally, to resume operation after power is restored, the machine must perform a home position return.

For instance, the positioning of printer scanners utilizes the principle of incremental encoders. Every time it powers on, we can hear a series of crackling sounds as it searches for the reference zero point before it starts functioning.

Suitable for: Suitable for CNC machine tools and accessories, robots, automatic assembly machines, automatic production lines, textile machinery, packaging machinery (fixed length), printing machinery (synchronous), woodworking machinery, plastic machines, and more. It can be said that the precision and stability are quite good, and the price is reasonable, making it widely applicable.

Encoder

Encoder Diagram

Operating Principle: Encoders are sensors that directly output digital signals. They have several concentric tracks on their circular disc, with alternating light and dark sectors along each track. The number of sectors in adjacent tracks is double the previous one. The number of tracks on the disc corresponds to the number of digits in its binary code. On one side of the disc is a light source, and on the opposite side, there is a light-sensitive element for each track. As the disc is positioned differently, the light-sensitive elements convert to corresponding electrical level signals based on whether they are illuminated or not, forming a binary code from 2^0 to 2^(n-1). The more tracks there are, the higher the precision. Currently, there are 17-bit and 23-bit encoders available domestically.

Features: The advantage is that there's no need for a counter, and the corresponding digital code can be read at any position on the shaft without being affected by power outages or interference. In other words, even during a power outage, the encoder can know its current position as long as it's powered on. The disadvantage is that the structure and circuit are relatively complex, with high technical requirements.

Suitable Applications: Suitable for special machine tools, textile machinery, irrigation equipment, papermaking and printing, hydraulic gates, robots and robotic arms, precision measurement equipment, elevators, and other precision equipment. Encoders offer enhanced anti-interference characteristics and stronger data reliability, but at a higher cost.

Operating Voltage, Current Consumption:

Operating voltages typically include 10-30Vdc and 5Vdc ±10%, with voltage and current consumption determining the power supply's output power.

Signal Output:

Signal outputs include sine wave (current or voltage), square wave (TTL, HTL), collector/emitter open (PNP, NPN), and various pulse outputs. TTL is a long-line differential drive with 5V levels (symmetric A, A-; B, B-; Z, Z-), while HTL is push-pull with 10V levels (or push-pull) output. Incremental circular encoder, the interface of the signal receiving equipment for the encoder should correspond to the encoder.

Signal Connection:

Encoder pulse signals are typically connected to counters, PLCs, and computers. Modules connected to PLCs and computers come in both low-speed and high-speed versions, with varying switching frequencies, some low and others high.

Single-phase connection for single-direction counting and speed measurement.

A and B are interconnected for forward and reverse counting, direction determination, and speed measurement.

A, B, Z three-phase connection, for position measurement with reference position correction.

A, A-, B, B-, Z, Z- connections, featuring symmetrical negative signal connections, result in an electromagnetic field of 0 contributed by the current to the cable. Incremental encoder with low attenuation and excellent anti-interference capabilities, capable of transmitting over longer distances.

For encoders with TTL output featuring symmetrical negative signals, the signal transmission distance can reach up to 150 meters.

For HTL encoders with symmetrical negative signal output, the signal transmission distance can reach up to 300 meters.

Other main parameters, please refer to the sample as needed:

Cables or outlets, transmission distance, shaft load, vibration, shock, starting torque, rotor moment of inertia, etc.

Rotary Encoder

Incremental encoders produce pulses when rotating, and their position is determined by counting devices. When the encoder is stationary or there is a power outage, the position is remembered by the internal memory of the counting device. Thus, after a power cut, the encoder must not move at all. Additionally, there must be no interference or loss of pulses during the encoder's pulse output when power is restored, as any deviation in the starting point of the counting device's memory is unknown and can only be detected when incorrect production results occur.

The solution is to increase reference points; each time the encoder passes a reference point, it corrects the reference position into the memory location of the counting device. Prior to the reference points, accuracy of position cannot be guaranteed. Therefore, in industrial control, there are methods such as finding the reference point first for each operation and zeroing out at startup.

For instance, the positioning of printer scanners utilizes the principle of incremental encoders. Each time it powers on, we can hear a series of clicks as the incremental encoder parameters seek the reference zero point before it starts functioning.

This method can be cumbersome for some industrial control projects, and even prohibits zeroing out after boot-up (the exact position must be known immediately upon booting), which is why encoder positioning has emerged.

Incremental Circular Encoder - Encoder Manufacturer (Online Inquiry) - Encoder provided by Suzhou Bilixin Photoelectric Co., Ltd. Suzhou Bilixin Photoelectric has dedicated much enthusiasm and passion to the field of optical metrological equipment. Suzhou Bilixin Photoelectric always centers on customers and creates value for them, winning the market with quality and service. We sincerely hope to cooperate with all sectors of society to achieve success and brilliance together. For related business inquiries, please contact Mr. Xie.