In the data acquisition world, resolution most often is expressed as a number of bits, such as 12, 16, or 20. For example, printer manufacturers often describe resolution as dots per inch, which is easier to relate to than dots per page. It is expressed as a fraction of an amount to which you can easily relate. In relative amounts, resolution describes the degree to which a change can be detected. An example of an accuracy specification and what can be expected of the reading is found in Table 1. Typically, gain errors depend on the magnitude of the input and usually are expressed as a percentage of the reading. Offset parameters, usually expressed as an absolute amount such as volts or ohms, generally are independent of the magnitude of the input. Most accuracy specifications include a gain and an offset parameter. It can be defined in several different ways and is dependent on the specification philosophy of the supplier as well as product design. AccuracyĪccuracy describes the amount of uncertainty that exists in a measurement with respect to the relevant absolute standard. Keep in mind, too, that it is rare when more resolution comes without penalizing acquisition speed. You should pay equal attention to these parameters when selecting a product. The reality is that accuracy and sensitivity are of equal or greater importance than resolution. There is a false implication that the higher the resolution, the better suited the product is to make measurements. Actually, the 14-bit board may be a better choice if it is more accurate and has better sensitivity than other higher-resolution products. As a result, you assume that an A/D board with 16-bit resolution is better than a 14-bit board, and a 20-bit board is still better. The most common mistake is to assume that more resolution always represents a better measurement. Even experienced engineers confuse these related, yet very different, specifications. Product characteristics such as price and measurement speed are easily understood.īut when you examine the resolution, accuracy, and sensitivity of a product, be careful. When selecting an analog-to-digital (A/D) board, an external data acquisition system, or other measurement device, many parameters must be considered. This article is part of TechXchange : Why Low Iq is the Smart Thing to Do

Effective resolution calculator