With respect to sensors, an NPN device is one that can switch the negative side of the
circuit, while a PNP device switches the positive side.
An Inductive proximity switch is used to detect metal objects within specific operating ranges.
The sensor emits a magnetic field and detects metallic objects when they move into the field
without the need for contact. This sensor suits both normally open, and normally closed applications.
Advantages of inductive proximity sensors include insensitivity to water, oil, dirt, non-metallic
particles, surface finish, and the ability to withstand high shock and vibration environments.
Because the sensor does not require physical contact it is particularly useful for applications
where access presents challenges or where dirt is prevalent. These sensors are ideal for
measuring and control applications, and suit a wide variety of automated automotive and
industrial processes such as hoists, tail lifts, dump trucks, waste / garbage trucks, diggers etc.