When I began working in the industrial sensor industry back in the mid-’90s, the standard sensing range for a size M12 flush-mount inductive proximity sensor was 2.0 mm. Advances in sensor technology later brought about so-called “Extended Range” proxes, with M12 flush-mount proxes rated at 4.0 mm nominal sensing distance. Another popular term for these extended range proxes is “2X”, as in “Two Times” the standard sensing range.
Today, competition and time has brought down the prices of most 2X sensors close to or equal to the prices for standard “1X” sensors. As a result, there’s a large and growing industry trend to just go ahead and standardize on 2X sensors. And why not? If the cost is essentially the same, dollar for dollar a sensor with more range is a more versatile sensor. The availability of longer range in smaller housings is driving migration from M18 bodies to M12 bodies, and from M12 housings to M08 housings. This saves money and helps reduce the size and weight of modern machinery.