Common-Mode Bias Current
The NI 9234 uses common-mode bias current to bias the current-
limiting diodes when IEPE current is turned off. When the NI
9234 is using grounded signal sources, this current causes an
error that is dependent on the AI- lead impedance. This error is
approximately 50 ppm of range and 15 ppm of reading per ohm
of AI- impedance. The common-mode bias current causes an
error only with grounded sources and is not an issue with floating
signal sources. For best accuracy, use low-impedance leads when
connecting grounded signal sources.
NI 9234 Getting Started Guide
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© National Instruments
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