Hioki Super megohm SM7110 - Page 171

Appx.3
Sample calculation of resistance measuring accuracy (SM7110)
Appx. 3 Sample calculation of resistance measuring
accuracy (SM7110)
1. Measure a current value owing through the measuring object (monitor a current value using current measuring
mode) and calculate the resistance of the measuring object. Assuming that the current value stands at 1.00000
nA, the resistance value is found from the following formula.
R: Resistance of measuring object
V: Measuring voltage
I : Current value owing through measuring object
R =
I
V
100.0 [V]
= 100.000 [G
Ω
]
1.00000 [nA]
=
2. Calculate current measuring accuracy
1.00000 [nA]
0.00520 [nA]
±(
×
100) = ±0.52 [%]
±(1.00000 [nA]×0.5 [%]+0.00001 [nA]×20 [dgt] = ±0.00520 [nA]
Calculation of reading error
Calculation of full-scale error
3. Calculate voltage generating accuracy.
±(100.0 [V]×0.1 [%]+100.0 [V]×0.05 [%] = ±0.15 [V]
0.15 [V]
100.0 [V]
±(
×100) = ±0.15 [%]
4. Calculate insulation resistance measuring accuracy.
±(0.52 [%]+0.15 [%]) = ±0.67 [%]
±(100.000 [G
Ω
]×0.67 [%]) = ±0.670 [G
Ω
]
Appx.