National Instruments NI USB-9421 用户手册

© National Instruments Corporation

Operate the NI USB-9421 only as described in these operating instructions.

Although the NI 9421 module may have more stringent certification standards than 

the NI USB-9421, when used with the NI USB-9162 carrier, the combined system may be 
limited. Refer to the 

 section for more details.

This icon denotes that the component may be hot. Touching this component 

may result in bodily injury.

Do not disconnect I/O-side wires or connectors unless power has been switched 

off or the area is known to be nonhazardous.

Do not remove modules unless power has been switched off or the area is known 

to be nonhazardous.

The NI USB-9421 is not certified for use in hazardous locations.

If hazardous voltages are connected to the module, take the following 
precautions. A hazardous voltage is a voltage greater than 42.4 V

pk

 or 

60 VDC to earth ground.

Ensure that hazardous voltage wiring is performed only by qualified personnel 

adhering to local electrical standards.

Do not mix hazardous voltage circuits and human-accessible circuits on the same 

module.

Make sure that devices and circuits connected to the module are properly 

insulated from human contact.

When module terminals are live with hazardous voltages, make sure that the 

terminals are not accessible by using the high voltage screw terminal backshell. Refer to 
the 

 section for more information.