National Instruments 4-Channel 用户手册
NI USB-9215 Series User Guide and Specifications
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NI USB-9215 Series Circuitry
The NI USB-9215 Series channels share a common ground. The
NI USB-9215 protects each channel from overvoltages. For more
information about overvoltage protection, refer to the
NI USB-9215 protects each channel from overvoltages. For more
information about overvoltage protection, refer to the
section. The signal is buffered and conditioned by the instrumentation
amplifier and is then sampled by a 16-bit ADC. The channels have
independent track-and-hold amplifiers that allow you to sample all
four channels simultaneously.
amplifier and is then sampled by a 16-bit ADC. The channels have
independent track-and-hold amplifiers that allow you to sample all
four channels simultaneously.
Figure 13. Input Circuitry for One Channel on the NI USB-9215 with Screw Terminal
The NI USB-9215A with BNC has a resistor that ensures the input voltage
does not drift outside of the common-mode range.
does not drift outside of the common-mode range.
Figure 14. Input Circuitry for One Channel on the NI USB-9215A with BNC
COM
AI+
+
AI–
–
NI USB-9215 with Screw Terminal
Isolated
ADC
Overvoltage
Protection
Overvoltage
Protection
NI USB-9215A with BNC
AI+
AI–
+
–
Instrumentation
Amplifier
Isolated
ADC
Overvoltage
Protection
Overvoltage
Protection