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NI 9205 Operating Instructions and Specifications
24
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Absol
u
te acc
u
racy form
u
las
AbsoluteAccuracy = Reading · Gai Range · Offse
NoiseUncertainty
GainError = ResidualGai GainTempco ·
TempChangeFromLastInter ReferenceTempco ·
TempChangeFromLastExternalCal
OffsetError = ResidualOffse OffsetTempco ·
TempChangeFromLastInter INL_Error
NoiseUncertainty =
(
RandomNoise ·
3) /
for a coverage factor of 3
σ
and
averaging 100 points.
Absol
u
te acc
u
racy at f
u
ll scale on the analog inp
u
t channels is determined
u
sing
the following ass
u
mptions:
TempChangeFromLastExternalCal =
70 °C
TempChangeFromLastInternalCal =
1 °C
NumberOfReadings =
100
CoverageFactor =
3
σ
For example, on the 10 V range, the absol
u
te acc
u
racy at f
u
ll scale is as follows:
GainError
= 115 ppm + 11 ppm · 1 + 5 ppm · 70
GainError
= 476 ppm
OffsetError
= 20 ppm + 44 ppm · 1 + 76 ppm
OffsetError
= 140 ppm
NoiseUncertainty
= (240
μ
V
·
3) /
Noise Uncertainty
= 72
μ
V
AbsoluteAccuracy
= 10 V · 476 ppm + 10 V · 140 ppm + 72
μ
V
AbsoluteAccuracy
= 6,232
μ
V (ro
u
nds to 6,230
μ
V)
100
100