1  AND 10 k HIGH PRECISION TRANSPORTABLE SETUP TO CALIBRATE MULTIFUNCTION ELECTRICAL INSTRUMENTS

A temperature controlled 1 {Omega}-10 k{Omega} standard Resistors transportable setup was developed at National Institute of Metrological Research, (INRIM) for the calibration and adjustment of multifunction electrical instruments. The two Standards consist respectively of two 10 {Omega} and 100 k{Omega} parallel connected resistors nets inserted in a temperature controlled aluminium box. Novelty of the realization is the oil insertion of the 1 {Omega} net with its internal connectors lowering the thermo-electromotive forces (emfs) effects. Short and mid-term stabilities of the setup Standards resulted on the order and in some cases better than other top level 1 {Omega} and 10 k{Omega} commercial Standards. The transport effect turning off the setup temperature control did not cause appreciable measurement deviations on the two Standards. The Standards uncertainties meet those requested by DMMs and MFCs manufacturers to calibrate and adjust these instruments. A test to adjust a multifunction calibrator gave satisfactory results.

A temperature controlled 1  and 10 kΩ transportable setup was developed at National Institute of Metrological Research (INRIM) for the calibration and adjustment of multifunction electrical instruments as digital multimeters (DMMs) and multifunction calibrators (MFCs). The two standards are made of two 10  and 100 k resistor nets connected in parallel and inserted in a temperature controlled aluminium structure. Novelties of the realization are the oil insertion of the 1  net with the internal side of the connectors lowering the thermo-electromotive forces (EMFs) effects, and the possibility to know instantly the temperatures of the environment, of the internal of the structure and the last calibration values of the 1  and10 kΩ standards. Short- and mid-term stabilities of the setup standards resulted on the order and in some cases better than other metrology-grade 1  and 10 kΩ commercial items. The transport of the setup even turning off its temperature control did not cause appreciable measurement variations on the two standards. The standards uncertainties meet those requested by DMMs and MFCs manufacturers to calibrate and adjust these instruments. A test to adjust a MFC gave satisfactory results.