Resolution, Accuracy, and Precision of Encoders
When you’re choosing an encoder for a motion control system, you’ll be faced with numerous technical terms. The amount of data available can be overwhelming. Which critical terms should you focus on first, and which can be deferred?
This paper looks at three important concepts that deserve your attention: resolution, accuracy and precision.
At first glance, it may seem that all three mean roughly the same thing. You may wonder if they’re interchangeable; indeed, many people speak of them as if they are. After all, if an encoder has high resolution, doesn’t that mean it’s accurate? And if it’s accurate, then it has to be precise, right? (Please note: the answer to these last two questions is a firm no.)
In fact, the terms are independent of each other. Each refers to a specific encoder characteristic, and they are not interchangeable. To clear up any confusion, we’ll first explain what resolution means for incremental encoders, then note any differences for linear and absolute encoders. We’ll move on to accuracy, and finish with precision. Along the way, we’ll give tips on how to use knowledge about each term to make the best encoder selection, and how to calibrate a system once the encoder is in place.