Longer cable lengths are more susceptible to noise. It is crucial to use proper cable lengths to ensure the system functions correctly. It is recommended to use shielded, twisted-pair cables with preferably low capacitance value.
The rating for capacitance value is normally in capacitance per foot. The importance of this rating is for well defined squarewave pulse outputs from the encoder rather than "jagged" or "saw-toothed" like pulses due to the interference of noise. Index Channel The index channel is an optional output channel which provides a once per revolution output pulse.
This pulse allows for the user to keep track of position and establishes a reference point. This output channel is extremely valuable for incremental encoders when an interruption of power occurs. In instances with a power failure, the last sustained index channel can be used as a reference marker for a restarting point.
Therefore, when such an occurrence takes place, an index channel can prove to be quite valuable in applications utilizing incremental encoders. Absolute encoders do not have an issue with losing track of position in power loss situations, because every position is assigned a unique bit configuration. Enclosed cover options help protect the encoder from dust particles.
Base options play a significant role in large vibration environments. Such mounting options are transfer adhesives which stick directly on the back of the encoder to the mounting surface, molded ears for direct mounting. Anaheim Automation also offers various base options for mounting purposes.
Anaheim Automation offers a selection of cover and base options to meet your application needs. After selecting the appropriate motor, it is important to know how to properly install it. The installation of each encoder is dependent upon its mounting or base option.
If an encoder is to be mounted to a motor shaft, then a centering tool can be used to align the hole of the encoder to the shaft. The different mounting options have varying functionalities. A T-Option however, uses adhesive to stick to the back of a motor.
For step by step instructions on installing an Anaheim Automation encoder, watch our video tutorials here. Anaheim Automation also provides the option of an encoder adder , where we mount the encoder for you, hassle free!
This assistance is offered to help the customer in choosing Anaheim Automation products for a specific application. However, any selection, quotation, or application suggestion for an Encoder, or any other product, offered from Anaheim Automation's staff, its' representatives or distributors, are only to assist the customer. In all cases, determination of fitness of the custom Encoder in a specific system design is solely the customers' responsibility.
While every effort is made to offer solid advice regarding the Encoder product line, as well as other motion control products, and to produce technical data and illustrations accurately, such advice and documents are for reference only, and subject to change without notice.
Problem: No output Solution: No output may be a result of various factors. Steps can be taken to ensure the proper functionality of the encoder. No mechanical movement results in any signal being output from the encoder. To correct this issue, observe if the encoder is rotating. Having loose connections or improper voltage supply may not allow the encoder to function properly. Finally, ensure the correct signal type e. If the problem persists, swap encoders, if possible, to determine if the encoder is the issue.
Problem: Unable to find index pulse Solution: The index pulse, or reference marker, is a once per revolution output of an encoder and is best found using an oscilloscope. Problem: Count output indicates incorrect direction Solution: If the count output indicates an incorrect direction then check for the wire configuration. See if any wires are reversed. If they are reversed, simply swap wires. NOTE: If your application is using index, reversing the wire configuration causes the reference alignment to also change.
If so, please make the appropriate changes to your application. Problem: Encoder is not rotating Solution: When encoders are exposed in open environments, dust and debris particles may accumulate around the shaft. Simply clean the exposed area and ensure that there are not objects obstructing the encoder from rotating. Problem: Noise Interference Solution: To improve the noise immunity of encoders it is strongly advised that no other electrical equipment be nearby or be kept at a fair distance.
Encoder cables should also be shielded and proper wires should be grounded to minimize electrical noise. Accuracy — difference in distance between the theoretical and the actual position. Cycles Per Revolution CPR - Cycles per revolution are the number of output pulses per complete revolution of the encoder disk Encoder - is a sensor of mechanical motion that generates digital signals in response to motion. Incremental Encoder - device that provides a train of pulses due in response to mechanical motion.
The output of this encoder is in form of a squarewave. Index - a separate output channel which provides a single pulse per shaft revolution. It can be used to establish a reference or marker for a starting position. Interpolation - is the method of increasing the resolution of an encoder.
This method allows for the encoder to produce a higher resolution output without increasing the overall size of the disk and encoder. Line Driver - is a sourcing output. A sinking input is required for line driver applications. Open Collector - is a sinking output. A sourcing input is required for open collector applications.
Pulses Per Revolution PPR - the total number of pulses produced per full revolution of the encoder shaft. Push-pull - is a combination between a line driver and an open collector.
Quadrature Encoder - two output channels which are out of phase by 90 electrical degrees. From the phase difference, the direction of rotation can also be determined. Resolution — number of line increments on a disk. Resolution for incremental encoders is often referred to as cycles per resolution and for absolute encoders it is in terms of bits. Single Channel Encoder — has only one output channel and is used in speed applications. Squarewave - a repetitive waveform corresponding to high and low signals.
Encoder Quiz. Sense Direction B. Sense Speed Tachometers C. Position Feedback. Which of the following is a NOT difference between absolute and an incremental encoder? Absolute encoders provide a unique position. Absolute utilize concentric circles on a transparent disc while incremental encoders utilize evenly spaced opaque sections to determine movement.
Position Tracker B. Rotary sensor has a disk wheel that is attached on a shaft. Their special marks are located on its surface in contact zone. Such labels are transparent, and the disk surface between them is made of impenetrable material. In the case of a linear quadrature encoder , a scale replaces the measuring disk.
Special reader slider travels along it. The main working principle remains all the same. A quadrature encoder pulse in the form of a light beam comes from the source and, depending on the opposite type of surface solid or opaque , falls or does not fall into the receiver detector. Quadrature incremental encoder has two separate pins on the disk where this process takes place. There are sensing channels which act like signal detectors.
They are commonly called as channel A and channel B. These points have separate inputs and wiring. Therefore, the device have two signal receivers in the one particular moment. Incremental measurement also requires a starting point. So, there is a Z channel that displays the start zero position. Depending on whether the light hits a transparent mark or an opaque surface, the receiver captures or does not capture the signal.
This can be graphically represented as two diagrams with a rectangular form also called square waves. Rotary quadrature encoder is digital IC integrated circuit so it uses a binary code. Mike has created all kinds of projects that you can follow and build yourself, from a retro arcade cabinet to plantation shutters for your home. This is a problem that has plagued me with these cheap encoders.
Yeah, I have had lots of bounce problems with these encoders. Angular Position When objects rotate around an axis such as a shaft or axle, each point of the object follows a circular arc.
Direction The direction that the shaft is turning, either clockwise or counter-clockwise can be captured. Velocity Finally, in addition to the position and the direction, we can determine the speed at which the shaft is turning. Next Types of Batteries — Electronics Basics. About The Author. Related Posts. Cammie on September 2, at pm. Mike Murray on September 2, at pm. I hope to do one soon! Mel on September 3, at am. Thank you for this! Saved me a lot of trouble.
Care should be taken with choice of output driver; particularly over long cable runs or in noisy environments. The accuracy of the quadrature encoder output should also be taken into account as this will also be multiplied by the encoding factor. Like all encoders, choosing a quadrature encoder starts with your application. If your motor has a shaft, a shafted encoder with a coupler can be used. A hollow shaft encoder is another option mounted with the motor shaft going through the encoder for more accuracy.
If your motor is used in a contaminated or dirty environment or you are using a large vector motor, a bearingless or magnetic encoder will provide the most reliable feedback. Rotary Encoders. Condition Monitoring System.
Spare Parts and Accessories. Knowledge Center Technology Quadrature Encoders.
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