INTERNET-ASSISTED REMOTE CALIBRATION DEMONSTRATED.
NIST has demonstrated an Internet-assisted calibration of an electronic instrument located at the Sandia National Laboratories (SNL). This is the first example of a so-called "e-calibration" in the electrical area on a remote programmable instrument for a NIST customer. The instrument under test at SNL was a multifunction calibrator used to calibrate the five electrical measurement functions available on most digital multimeters (DMMs). The reference at NIST for this test was a commercial multifunction calibrator, which is periodically characterized using basic NIST electrical standard artifacts. Artifact calibration of commercial calibrators also is used at many industrial standards laboratories; however, even with automation, it takes a skilled metrologist about one week to perform the characterization. The objective of the new e-calibration service is to relieve NIST customers of this burden by performing an in situ calibration of their calibrator using a precision DMM, calibrated by the NIST-characterized multifunction calibrator, as a traveling transfer standard. The DMM and the calibrators are fully programmable, and the control software used to calibrate them implements a test set-up and the test parameters for each instrument. It is critical that the same test procedures are employed at both laboratories.
A password-accessible calibration report for the SNL calibrator was posted to evaluate the usefulness of electronic test reports. With further refinements, it is expected that this new calibration process will become a NIST Special Test next year.