Serving as measurement feedback devices in paper bill detector of ATMs, the PR 750 series AC-operated LVDTs, from Macro Sensor, ensure proper currency dispensing. Their output changes according to the thickness of the passing bill. No contact between the LVDT core and coil means no friction to cause inaccuracy or wear out during the service life of the ATM. A sample readout is made for one complete revolution to account for dirt accumulation on the roller. 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 and compensates for any variation of the roller surfaces.