National Instruments 9221 用户手册

下载
页码 28
© National Instruments Corp.
9
NI 9201/9221
The NI 9201/9221 with screw terminal has a 10-terminal, 
detachable screw-terminal connector. The NI 9201/9221 with 
DSUB has a 25-pin DSUB connector. Each channel has an AI 
terminal or pin to which you can connect a voltage signal. COM, 
the common terminal or pin, is internally connected to the isolated 
ground reference of the module.
The NI 9201/9221 channels are isolated from other modules in the 
system. The module protects each channel from overvoltages. 
Refer to th
 section for more information about 
overvoltage protection. The input signals are scanned, buffered, 
conditioned, and then sampled by a single 12-bit ADC. Refer to 
Figure 3 for an illustration of the input circuitry on the 
NI 9201/9221.
 
Figure 3.  Input Circuitry on the NI 9201/9221
NI 9201/9221
Buffer
Isolated
ADC
Overvoltage
Protection
Mux
COM
AI7
AI0