When the parts you work with can range from being extremely abrasive to easily deformed, or are in an environment that splashes water and oil, how to track them accurately without damaging the sensor can be a big concern.
The solution? Proximity sensors.
Proximity sensors are capable of detecting the presence of a target without contact. Having no part contact tied with no moving parts means higher durability and reliability with reduced maintenance and downtime.
In this guide, we’ll focus on inductive and capacitive proximity sensors, which are available through MISUMI.
Inductive Proximity Sensors
Much like a mini metal detector, an inductive proximity sensor detects metallic objects by using electromagnetic induction. This means that the sensor gives off a magnetic field that creates electrical currents within the conductive target, also known as “eddy currents.” These currents cause a magnetic loss, and it’s this change that triggers the sensor.
These sensors are best used in applications where the target is made of a metallic material. The aforementioned metal detector is a good example of durability due to being a tool typically used outdoors in water or in coarse, rough, and irritating sand that gets everywhere.
For more of an automated environment, these sensors perform well in part detection applications where accessibility is difficult and won’t trigger if covered in water or oil. They can also be used in position controls to determine the location of cylinders, linear actuators, and robotics.
Capacitive Proximity Sensors
Even though most phones with a screen are technically “touchscreen,” what actually allows your touch to complete an action is capacitive sensing. Capacitive proximity sensors send out an electrical field that a target’s capacitance will disrupt and store a charge. It’s this change that the sensor detects.
Capable of detecting both metallic and non-metallic targets, these sensors are best used in a less harsh environment where metal chips and debris aren’t being strewn about.
Your industry might see use for these in part detection applications similar to the inductive sensors above or in liquid and solid level detection to monitor the storage of your product.
To Shield or Not to Shield?
It’s important to understand the difference between a shielded and unshielded sensor.
Shielded allows the sensor to be mounted flush to a surface and removes the possibility of false triggering from the surrounding environment that isn’t directly in front of the face of the sensor. This will come at the cost of a smaller sensing range but is perfect for applications that require significant precision in a limited space.
Unshielded requires the sensor to be mounted proud to a surface and allows a wider sensing range at the potential cost of false triggering from its surroundings. These sensors are best in applications where space is not an issue, and a broader sensing area is necessary.
With this brief introduction to the differences between inductive and capacitive sensors, you can start your design with more confidence.
For a great example of proximity sensor applications, read “Benefits of a Remote System for Press Die Applications.”
Explore a wide range of inductive and capacitive proximity sensors from brands like Contrinex, Pepperl+Fuchs, OMRON, and ifm offered by MISUMI.
