Choice of test points in the measurement range of digital voltmeters

Conclusions

• 1. Test points should be established individually for each DV type on the basis of analyzing the instrument's circuit and principle of operation. This should be made by the instrument's developer in the course compiling its technical documents.

• 2. The basic range of digital voltmeters with a continuous error function should be tested at five-six points uniformly distributed along the range, but including without fail those nearest to the lower and upper range limits.

• 3. The basic range of pulse-code digital voltmeters should be tested at points with expected maximum errors of the DV discrete divider, and also at points affected to the greatest extent by the transient processes in comparison devices and by the possible skips in the output code. The technique for selecting such points is provided on the basis of the instrument's circuit analysis and its algorithm of operation.

• 4. Additional multirange digital voltmeter ranges formed by means of a measuring amplifier should be tested at the same points as the basic range.

• 5. Additional multirange digital voltmeter ranges formed by means of a linear divider (a shunt) should be tested at four points, consisting of those nearest to the upper and lower limits, and two points corresponding to the basic range points whose error values are closest to their tolerances.