How Displacement Sensor works

The Important parameters to be considered while selecting a displacement sensor are

• Contact/Non Contact: The selection of a contact or non contact sensor depends on your application. Although non contact technology seems advantages it is not possible to use non contact sensors for each and every application. Some non contact sensors like laser and ultrasonic sensors may be dangerous. The advantage of non contact sensors are that there is no mechanical contact so there is no friction and the sensor does not wear out. Hence operating cycles are more. Non contact sensors are more costly compared to contact sensors. Operating temperature and frequency response of a contact sensor is high. Some non contact sensors like ultrasonic sensors may have a blind range.
• Linear/Rotary motion: You need to check whether your distance to be measured is linear or rotary.
• Measuring range: The measuring range is another important factor. The manufacturer of the sensor provides the measuring range in the datasheet.
• Input voltage range
• Output: The output may be analog voltage output( for example 0.5 to 4.5V ), current output( for example 4 to 10mA ) or resistance output (for example 0 to 100ohm)
• Resolution: The Resolution of the sensor is the smallest change a sensor can detect in the quantity that it is measuring( for example resolution of 0.1mm )
• Accuracy: This specifies how accurate your reading is( for example +/-0.1mm )
• Operating temperature
• Degree of protection
• EMC protection
• Cable
• Cost

The above factor will help you to select the right sensor for your application. However some parameters such as EMC protection, cost ..etc may not be important at the start in some applications.

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