|Editor’s note: This tech tip is part 2 of a four-part series and covers why it is important to mount position sensors correctly and how to do it. The other two parts will be published in the next several Mechatronics Sense Newsletters. The first part can be read in the previous edition (Winter 2017).
How to Mount Non-Contact / Touchless Sensors For Reliable and Precise Angle Measurements
“Non-contacting” stands for the position measurement technology being one without mechanical electrical contacts, e.g. wipers or switches and “touchless” means that there is no mechanical connection between the rotating shaft on the machine side and the static sensor housing. Almost all “touchless” technologies are “non-contacting” ( or “contactless”).
Components and Usage
All Hall-Effect based non-contacting touchless sensors are made of two parts: the sensor housing itself, consisting of electronics including the Hall-Effect chip, the power supply and circuitry for digital or analog outputs and a magnetic marker, which is mounted on the rotating shaft of the machine. The magnet marker provides a directional magnetic ﬁeld orientation over 360° rotation, which is detected and translated into a deﬁned output signal with the help of the electronics in the sensor housing.
Hall-Effect sensors detect the magnetic ﬁeld orientation to obtain a physical position value and not the ﬁeld strength. These sensors also come with smart adjustment electronics to compensate for all kinds of magnetic ﬁeld variations, which include temperature variations and mechanical tolerances of shafts and mounting plates included in the design.
Mounting touchless rotary sensors involve four steps: (1) securing the sensing component (sensor) and the magnet properly, (2) selecting a magnet size based on the proximity the magnet is to be mounted to the sensor, (3) taking into account if your application is measuring with a material/surface between magnet and sensor when selecting magnet size and (4) ensuring proper alignment between magnet and sensor.
Article continues | READ MORE INCLUDING MOUNTING, SELECTING MAGNET & ALIGNMENT |