NI-9250 2-channel analog input module

Description

Common-mode rejection ratio
High-resolution mode (at DC and 50 Hz to 60 Hz)
Channel-to-COM 100 dB
COM-to-earth ground >170 dB
High-speed mode (at 0 Hz to 60 Hz)
Channel-to-COM 70 dB
COM-to-earth ground >150 dB
Input bandwidth
High-resolution mode 14.4 Hz
High-speed mode 78 Hz
High-resolution noise rejection (at 50 Hz and
60 Hz)
60 dB
Overvoltage protection ±30 V between any two inputs
Differential input impedance 78 MΩ
Input current 50 nA
Input noise
High-resolution mode 200 nVrms
High-speed mode 7 μVrms
Gain error
High-resolution mode
at 25 °C 0.03% typical
at -40 °C to 70 °C 0.07% typical, 0.15% maximum
High-speed mode
at 25 °C 0.04% typical
at -40 °C to 70 °C 0.08% typical, 0.16% maximum
Offset error
High-resolution mode 4 μV typical, 6 μV maximum
High-speed mode 14 μV typical, 17 μV maximum
Offset error from source impedance Add 0.05 μV per Ω, when source impedance
>50 Ω

NI-9232 Circuitry

Each channel passes through a differential filter and then is multiplexed and sampled by a 24- bit analog-to-digital converter (ADC). The channels share a common ground, COM, that is isolated from other modules in the system.

Common-Mode Voltage

The NI-9232 common-mode range is the maximum voltage between any channel and COM. If COM is not connected, then the common-mode voltage range is the maximum voltage between any two channels. The NI-9232 measures the common-mode voltage level of each channel and returns a warning in the software if the signal is outside the common-mode voltage range.

Safety Voltages
Connect only voltages that are within the following limits:
Between any two terminals ±30 V maximum
Isolation
Channel-to-channel None
Channel-to-earth ground
Continuous 250 Vrms, Measurement Category II
Withstand 2,300 Vrms, verified by a 5 s dielectric
withstand test