Electric actuators range from syringe-sized units in medical applications to those that drive truck-sized industrial presses. These ubiquitous muscles of precision motion usually incorporate an electric motor and rotary-to-linear device for conversion of torque to linear force. So let’s cover common motion applications for this component type. No matter the application, electric actuators deliver precision and repeatability—indispensable […]
FAQs + basics
Ways to wire an absolute encoder into a motion system
Absolute encoders are traditionally wired in one of three ways: in parallel, with a serial interface, or over a bus. The serial and bus interfaces have multiple protocols or standards, some of which are open-source, while others are proprietary to specific manufacturers. When considering how to wire an absolute encoder, the required resolution, level of […]
FAQ: How do magnetic encoders work?
Encoders, whether rotary or linear, absolute or incremental, typically use one of two measuring principles—optical or magnetic. While optical encoders were, in the past, the primary choice for high resolution applications, improvements in magnetic encoder technology now allow them to achieve resolutions down to one micron, competing with optical technology in many applications. Magnetic technology […]
FAQ: What are stacked piezo actuators and what do they do?
A piezo element is a ceramic that expands or contracts when an electrical charge is applied, generating linear movement and force. Multiple piezo elements can be layered on top of each other, creating what is known as a stacked piezo actuator. These devices take advantage of the combined effect of each element’s expansion to produce a useful […]
What are capacitive encoders and where are they suitable?
Two types of encoders dominate the general industrial market—optical and magnetic. But capacitive encoders, a relatively new introduction, offer resolution comparable to optical devices, with the ruggedness of magnetic encoders. Currently, there are only a handful of vendors for capacitive encoders, but their suitability for applications requiring high precision and durability make them a good […]
Determining pulses per revolution for an encoder application
Incremental encoders determine rotary position by generating a specific number of pulses per revolution (PPR) and counting those pulses as the encoder spins. The PPR rating indicates resolution, and is typically the most important factor when selecting an incremental encoder. But how do you determine what PPR is needed for a specific application? Fortunately, establishing the required […]
FAQ: What’s the difference between single and multi-turn rotary encoders?
Absolute rotary encoders output precise position information—even after a power-off condition—by assigning a unique digital value, or “word,” to each shaft position. But in applications where the encoder makes more than one revolution during the process, there is no way to know how many turns it has completed. At least not with the traditional type […]
Resolver versus encoder — what’s the difference?
Resolvers and encoders are both devices that measure the rotary position of a shaft by converting mechanical motion into an electrical signal. Resolvers have a longer history, originally used in military applications and adopted for industrial use due to their rugged design. But encoders are taking the place of resolvers in many applications. What’s driving the shift […]
FAQ: What do X1, X2, and X4 position encoding mean for incremental encoders?
An encoder is a device that measures position, and in some configurations, can also measure direction. Rotary encoders measure rotation of a shaft, while linear encoders measure distance traveled. For both types of encoder, the position measurement can be either incremental or absolute. An incremental encoder measures change in position, but does not keep track of […]
Linear encoder types — and parameters for selection
Linear encoders monitor linear movement and provide position feedback in the form of electrical signals. In servo driven systems, linear encoders supply the precise position of the load, typically in addition to the speed and direction feedback provided by the motor’s rotary encoder. For stepper driven systems, which typically operate in open-loop mode with no position […]