Some applications have multiple materials that have to be detected. When specifying a standard inductive proximity sensor the first question asked is, “what is the target material that will need to be detected.” In my previous post, I indicated that the ideal target for an inductive sensor is a target made from mild steel. This is correct; however, an inductive sensor can also detect non-ferrous materials but a correction factor has to be determined into the rated operating distance of your selected sensor. For example, if you select a sensor that has 4mm of operating distance (Rated Operating Distance), and the target is aluminum, we would multiply a correction factor of 0.30-0.45 to get the new rated operating distance of your sensor (1.2mm -1.8mm). Due to the aluminum’s non-ferrous material we can no longer achieve the 4mm rated operating distance in proximity to the aluminum target.
The approximate detection distance of a sensor for various metals can be estimated using the correction factors below.
Material / Approx. Sensing Range
- Mild Steel (Fe360) / 1.00 x rated
- Stainless Steel / 0.6 – 1.0 x rated
- Aluminum / 0.30 – 0.45 x rated
- Brass / 0.35 – 0.50 x rated
- Copper / 0.25 – 0.45 x rated
So, remember to always reference the type of material used in the application and use the correction factors to determine the correct sensor for your application. If the desired operating distance cannot be achieved with the first sensor selected, you may have to select a sensor with a longer rated operating distance to overcome the correction for the non-ferrous material.
If you have any questions on sensor selection or just simply need assistance selecting the correct sensor for your application we are here to help. For more information on inductive sensors, you can visit our new website.
