Sensors & Transducers


Capacitive position sensing

December 2002 Sensors & Transducers

The functional principle behind the capacitive analog position pick-up is similar to that of a capacitive proximity switch. It detects objects which are within its response range without touching them. The function is based on the effect on the electric field in the vicinity of its 'active sensor surface'. The basic structure of the sensor consists of an oscillator, a demodulator, the linearisation network and the controlled current source.

The criteria for an analog evaluation are the material properties, the size of the object involved, and its distance from the 'active sensor surface'. For objects deviating from the standard target, the maximum working distance is reduced.

In actual operation, the optimum calibration to be performed from the rear of the housing over a trimming potentiometer is signalled to the user by the adjacent LED. As a further special feature, this LED also signals if the load impedance at the output is too high or non-existent.

Advantages of the capacitive analog pick-up

The capacitive analog sensor scans objects without contact. This means that the object scanned is not subjected to any mechanical wear and tear. Nor do colours and surface roughness have any negative effect on the measured result. In the case of differing object materials, the output signal deviates from the standard output signal of 4-20 mA, and can be returned by a simple-to-perform user calibration procedure to the standard output signal.

Applications

The capacitive analog sensor makes linear evaluation of a position for the first time; as soon as an object is located within the sensor's measuring range, a precise output current is produced. Applications include: material selection, non-conductive material thickness, sheet-thickness measurement, height measurement, diameter measurement, static and dynamic displacement, orbit-tracing, concentricity and eccentricity, axial and radial shaft run-out and alignment.



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Miniature inductive sensors
ifm - South Africa Sensors & Transducers
The inductive IY/IZ type sensors from ifm are used in various industrial areas where space is limited.

Read more...
The expanding role of 3D cameras in industrial quality control
TANDM Technologies Sensors & Transducers
Across factory floors, warehouses, mines and research centres worldwide, computer vision paired with 3D camera technology is revolutionising quality control.

Read more...
PDS implementation on mines
Sensors & Transducers
Level 9 vehicle intervention for collision avoidance has been mandatory on South African mines since 2022, yet the effective roll-out of proximity detection systems remains slower than expected. This is not due to the technical limitations of integration but to operational readiness on site.

Read more...
Monitoring analogue process values
ifm - South Africa Sensors & Transducers
Everywhere in industry, electronic sensors are used to detect process values such as temperature, pressure or flow. Process value monitoring often takes place directly in the sensor.

Read more...
Protecting buildings’ embodied carbon with retrofitted systems
Schneider Electric South Africa Sensors & Transducers
The World Economic Forum has said that around 80% of the buildings in existence will still be around in 2050; it is therefore essential that in order to combat climate change we retrofit them for energy efficiency.

Read more...
Listening for damage to wind turbines
Sensors & Transducers
The Fraunhofer Institute for Integrated Circuits, working in concert with the Fraunhofer Institute for Wind Energy Systems, has developed a solution that can be used to identify cracks and breakage inside wind turbine blades remotely at an early stage.

Read more...
Enhancing gold leaching efficiency
Endress+Hauser South Africa Sensors & Transducers
Endress+Hauser offers a range of advanced technologies designed to enhance the stability and accuracy of pH and dissolved oxygen measurements on gold processing plants.

Read more...
Powering safer mining with PDS
Sensors & Transducers
With the mining industry under increasing pressure to prioritise safety without compromising productivity, Booyco Electronics is pushing the boundaries of Proximity Detection System and Collision Avoidance System technology across both underground and surface operations.

Read more...
The car of the future listens
Sensors & Transducers
The perception of external sounds in cars has been lacking, even in automated driving. That is why Fraunhofer IDMT-HSA is researching the integration of acoustic sensor technology in its KI4BoardNet project with the Hearing Car.

Read more...
High-performance LineScan camera
Sensors & Transducers
Lynred, a global leader in infrared imaging technologies, has launched its next-generation SWIR LineScan camera and sensor, specifically designed for the inspection of silicon wafers, solar panels and waste management.

Read more...









While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.




© Technews Publishing (Pty) Ltd | All Rights Reserved