TITLE:
Automated Multi-Meter Method for the Scaling of Low AC Voltage from 200 mV to 2 mV
AUTHORS:
Rasha S. M. Ali, Hala A. Mageed, N. N. Tadros
KEYWORDS:
Micropotentiometer; Low ac Voltage Calibration; ac-dc Difference; Digital Multimeter; Step Down Procedure
JOURNAL NAME:
Energy and Power Engineering,
Vol.5 No.2,
March
29,
2013
ABSTRACT:
A set of seven single junction thermal converter Micropotentiometers
(μPots) has been constructed at the National
Institute for Standards (NIS), Egypt. This set has been built to cover the low ac voltage ranges from 2 mV to 200 mV at
frequencies from 40 Hz up to 20 kHz. The construction of the μPots set has been presented and an adopted
calibration method has been performed as well. This method has been performed by
means of a step-down procedure using a Digital Multi-Meter (DMM). The scaling procedures
have been carried out in sequential steps starting from the calibration of the 200 mV-μpot by using DMM that is accurately calibrated
at its 200 mV ac voltage range down to
2 mV-μPot. Furthermore, a new automatic
calibration system has been established to achieve the scaling procedures. This
system has been specially designed using Laboratory Virtual Instrument Engineering
Workbench (LabVIEW) software to overcome the deficiencies of manual methods. The
automatic calibration has been investigated of all mPots at different frequencies. The ac-dc differences for the μPots and their uncertainty evaluation
from 2 mV to 200 mV at different frequencies from 40 Hz to 20 kHz have been determined.