In addition the complement of each channel is available, making a total of six output signal lines. Associated counting equipment monitors this relationship and determines the shaft direction. The quadrature relationship in association with external circuitry can also provide the ability to multiply the output signals by four.
Thus a increment model can provide 20, increments per revolution. The signal is used as an exact reference point to coordinate the serial pulse train with a known mechanical location.
To use this effectively, it is necessary to install the encoder with a clamp mounting bracket, or some other means that will allow the body of the encoder to be turned. A known relationship can be provided if specified in the part number selected.
NOTE: this option is not available for some high increment models. Each individual increment forms its own unique code on a parallel output bus. Therefore, even if the power fails, once restored, the position of the shaft is immediately known without any resetting routine, as is required with Incremental encoders. The main consideration is that standard Absolute encoders only provide this feature for one shaft revolution. If more turns are required it is necessary to use some form of mechanical reduction, or select one of our Multi-Turn Absolute encoders.
This type has an internal mechanical arrangement that drives multiple absolute code disks. Multi-turn absolute encoders are available with resolutions up to 30 bits, this is achieved with a mechanical build that has 14 bit 16, turns of the shaft, and 16 bits 65, for each shaft revolution.
Refer to our web site for full technical details for each interface. In the past there was a range of five different output options, available for some of the series, providing for all types of input structures to which encoders may be connected. Motor encoders are used for more precise speed control in applications using AC motors, and often times need to have more robust IP, shock and vibration parameters.
Servo motors encoders permanent magnet motor encoders offer closed loop feedback control systems to applications that require higher precision and accuracy, and are not as robust as AC induction motors. The motor encoder used on servo motors can be modular, incremental or absolute depending on the level of resolution and accuracy required.
Stepper motors are cost effective, precise, and are typically used in open-loop systems. In systems using stepper motors where speed control is required, an incremental motor encoder is often mounted to this motor and will allow the stepper motor system to achieve closed loop feedback. Stepper motor encoders can also be used in some applications to allow for improved control of stepper motors by providing precision feedback of the location of the motor shaft in relation to the step angle.
DC motor encoders are used for speed control feedback in DC motors where an armature or rotor with wound wires rotates inside a magnetic field created by a stator. The DC motor encoder provides a mechanism to measure the speed of the rotor and provide closed loop feedback to the drive for precise speed control.
The next factor impacting motor encoder selection is the mounting option, and the most common options are:. The application in which the motor encoder is being utilized will determine the motor encoder technology that needs to be used. The two broad types of motor encoder technologies available are:.
A: A quadrature has two output channels, with repeating squarewaves, which are out of phase by 90 electrical degrees. Q: What is an index pulse? A: The index pulse, also referred to as a reference or marker pulse, is a single output pulse produced once per revolution. Q: What other types of encoder technologies are there?
A: There are two types of encoder technologies. Q: What types of applications are encoders implemented in? A: They are frequently utilized in stepper motors , automation, robotics, medical devices, motion control and many other applications requiring position feedback.
Q: Does any encoder disk codewheel work with any encoder module? A: No, each resolution and each disk diameter works with a different encoder module.
Q: What is PPR? A: PPR stands for pulse per revolution in rotational motion for rotational motion and pulse per inch or millimeter for linear motion. Q: When can a single output channel be used in an incremental encoder? A: A single output channel for an incremental encoder can be used when it is not important to sense direction. Such applications make use of tachometers. Q: Will Anaheim Automation mount an encoder to motors? A: Yes, a special part number would be created for including the encoder attached to a motor.
Required Maintenance. Encoders require very little maintenance due to their ruggedness and reliability. However, it is recommended to minimize an encoders exposure to dust particles or debris and also, unless designed for exposure to water or moisture. Also, under duress of shock and vibrations, encoder discs may become scratched resulting in encoder failure. If such an event occurs, the disc may need to be replaced to provide accurate readings.
The following environmental and safety considerations must be observed during all phases of operation, service and repair of an encoder. Failure to comply with these precautions violates safety standards of design, manufacture and intended use of an encoder. Please note that even with a well-built encoder, products operated and installed improperly can be hazardous.
Precaution must be observed by the user with respect to the load and operating environment. The customer is ultimately responsible for the proper selection, installation, and operation of the encoder. Do not operate the encoder in the presence of flammable gases, dust, oil, vapor or moisture.
For outdoor use, the encoder must be protected from the elements by an adequate cover, while still providing adequate air flow and cooling. Due consideration should be given to the avoidance of liquids and vapors of any kind. Contact the factory should your application require specific IP ratings. It is wise to install the encoder in an environment which is free from condensation, dust, electrical noise, vibration and shock. Additionally, it is preferable to work with encoders in a non-static, protective environment.
No work should be performed while power is applied. Don't plug in or unplug the connectors when power is ON. Wait for at least 5 minutes before doing inspection work on the encoder after turning power OFF, because even after the power is turned off, there will still be some electrical energy remaining in the internal circuit of the encoder circuitry. Plan the installation of the encoder in a system design that is free from debris, such as metal debris from cutting, drilling, tapping, and welding, or any other foreign material that could come in contact with the circuitry.
The lifetime of an encoder is dependent on various factors such as environmental exposure and application use. By limiting the exposure of the encoder to electrical equipment, temperatures above recommended values, condensation, and vibration and shock, and using the encoder as directed by the manufacturer can extend the lifetime of an encoder. Along with the encoder line, Anaheim Automation carries a comprehensive line of single-ended and differential encoder cables with four, six, and eight leads, cable lengths up to 16 feet, and encoder centering tools.
Additionally, Anaheim Automation offers an extended line of stepper , brushless , and servo motors which can implement encoders for your application needs. What is an Encoder? Block Diagram for Encoders Basic Types of Encoders Linear and rotary encoders are broken down into two main types: the absolute encoder and the incremental encoder. Incremental Encoder. Single-Ended Encoder. Differential-Type Encoder. Encoder Guide What is an Encoder? Absolute Encoder An absolute encoder contains components also found in incremental encoders.
Linear Encoder A linear encoder is a sensor, transducer or reading-head linked to a scale that encodes position. Magnetic Rotary Encoder A magnetic encoder consists of two parts: a rotor and a sensor. How do Commutation Encoders Work? How are Encoders Controlled? Physical Properties Linear Encoders The key components of a linear encoder are a scanning unit, sensor, transducer or readhead, paired with a transmissive or reflective scale, which encodes position.
Rotary Encoders The key components of a rotary encoder are the disk, light sources and detectors, and electronics. Incremental Encoders Differential-Type Encoder The key components of an incremental encoder are a glass disk, LED light emitting diode , and a photo detector. Where are Encoders Used? Applications for Encoders An encoder can be used in applications requiring feedback of position, velocity, distance, etc.
Advantages of an Encoder - Highly reliable and accurate - Low-cost feedback - High resolution - Integrated electronics - Fuses optical and digital technology - Can be incorporated into existing applications - Compact size Disadvantages of an Encoder - Subject to magnetic or radio interference Magnetic Encoders - Direct light source interference Optical Encoders - Susceptible to dirt, oil and dust contaminates Troubleshooting PLEASE NOTE: Technical assistance regarding its Encoder line, as well as all the products manufactured or distributed by Anaheim Automation, is available at no charge.
Encoder Quiz 1. What are single output channel incremental encoders used for? Position Feedback 2. Which of the following applies to an Index Channel? All of the Above 4. What does an Encoder do? What does CPR stand for? Describe the different types of encoder outputs below.
Which of the following are encoder advantages? All of the Above 8. Quadrature channels are out of phase by how many electrical degrees? List the criteria for selecting an encoder: 1.
Required Maintenance Encoders require very little maintenance due to their ruggedness and reliability. Environmental Considerations for an Encoder The following environmental and safety considerations must be observed during all phases of operation, service and repair of an encoder.
Lifetime of an Encoder The lifetime of an encoder is dependent on various factors such as environmental exposure and application use. It works like a human arm with pivot, rotation and slide movements. The signal input from the controller is converted into motion by the actuator, and the robot is moved precisely. In industrial robots, by changing the end effector, it is possible to handle not only grabbing but also painting and welding.
If you visit a robot or machine tool exhibition, you can actually see the articulated robots on display by various companies. Motors are used as robot actuators because they are easy to miniaturize and have high accuracy. In actual cases, people use actuators with increased rotational force torque by integrating a reduction gear that works the same as a bicycle transmission to the output shaft of the motor and slowing down the rotational speed of the motor.
There is also an electric slider that generates a large force in the direction of movement by changing the movement from rotational to linear with a screw. You can also see these in exhibitions. There are so many types of motors, and so confusing. We will focus on the motors that use encoders in this article. One example is a servomotor. The servomotor is the motor that is used in the servomechanism.
The servomechanism is the mechanism that keeps the speed of continuous rotational motion or linear motion constant, or precisely controls the rotation angle and travel distance of one movement. The servo motor consists of a brushless DC or AC motor, an encoder, and a servo amplifier also called a driver. In order to keep the rotation speed of a brushless DC motor or AC motor constant, an encoder detects the rotation speed.
The servo amplifier controls to rotate the motor faster if the detected speed is slower than the set rotation speed, or to slower if it is faster. In order to accurately control the rotation angle of the motor, an encoder detects the rotation angle.
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