Visit the Inertial Aerosystems UK web site

Linear position sensors used in ATM bill detector

A Macro Sensors product story
Edited by the Engineeringtalk editorial team May 6, 2009

Macro Sensors has revealed how its PR 750 series of 3/4in (19mm) diameter AC-operated LVDTs are serving as measurement feedback devices in the paper bill detector of ATMs.

In an automated teller machine (ATM) the linear position sensors are used to measure the separation of a pair of rollers, whereby bills passing between the rollers displace the LVDT core.

As the bills pass between the rollers, the LVDT output changes according to their thickness.

As a typical bill measures 0.0003in (0.0075mm) thick, the LVDT will detect any derivation should two or more bills get stuck together.

As the ATM can be used hundreds of times a day, the repeatability and reliability of the linear position sensor are of key importance.

Since there is no contact between the LVDT core and coil of the PR series, there is no friction to cause inaccuracy or part of the LVDT to wear out during the service life of the ATM.

To account for any dirt accumulation on the rollers, a sample readout is made for one complete revolution.

Any zero-offset value is stored and, then, compared against the LVDT output as the customer's currency is measured.

This eliminates the risk of passing an unexpected number of bills, while at the same time compensates for any variation of the roller surfaces.

Not what you're looking for? Search the site.

Back to top Back to top

Google Ads

 

Contact Macro Sensors

Related Stories

Contact Macro Sensors
Newsletter sign up

Request your free weekly copy of the Engineeringtalk email newsletter ...

Visit the Inertial Aerosystems UK web site

Articles by product category

All suppliers A - Z

A Pro-talk Publication

A Pro-talk publication