3, induction proximity sensor
Inductive proximity sensors are solid-state electronic devices that detect the position of metal targets by interference of their energy fields. No physical contact is required, and there are no moving parts to block, wear or break, resulting in less maintenance.

The lack of moving parts also means it is not affected by dust or dirt. There are a large number of shapes and sizes to choose from, so inductive proximity sensors are highly customizable for a variety of applications. Inductive proximity sensors require external power (electricity) to work and cannot handle large current loads.
In addition, they may be susceptible to electrical noise, RF interference, leakage current, and voltage drop. Inductive proximity sensors are sometimes adversely affected by extreme temperature fluctuations and moisture intrusion.

4、Limit switch

The limit switch uses a unique hybrid technology to detect the position of iron-containing targets through electromagnetic fields. Rugged, long-life, rodless limit switches are extremely reliable in harsh environments and difficult applications. No physical contact or external power supply is required, so no clogging, bending, breaking or grinding and high current loads are possible.

Like mechanical switches, they are not polarity or voltage sensitive and are not affected by electrical noise, RF interference, leakage current and voltage drop.

Limit switches are not affected by dust, dirt, moisture, physical contact, or most corrosive or chemicals. Most models are intrinsically safe and have a wide operating temperature range.

With its sealed contacts and all-metal housing, rodless limit switches are ideal for explosion-proof and waterproof applications.

Position sensors play an important role in industrial automation. There are several different position sensor technologies available, each with a unique set of performance characteristics. Care should be taken to select the right type of sensor for the application to achieve the desired reliability and performance.