National Instruments 8-Channel, 24 V Logic, Sinking Digital Input Device Computer Hardware User Manual


 
© National Instruments Corporation 3 NI USB-9421 User Guide and Specifications
Safety Guidelines
Operate the NI USB-9421 only as described in these operating instructions.
Note 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 Specifications section for more details.
Hot Surface This icon denotes that the component may be hot. Touching this component
may result in bodily injury.
Caution Do not disconnect I/O-side wires or connectors unless power has been switched
off or the area is known to be nonhazardous.
Caution Do not remove modules unless power has been switched off or the area is known
to be nonhazardous.
Caution The NI USB-9421 is not certified for use in hazardous locations.
Safety Guidelines for Hazardous Voltages
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.
Caution Ensure that hazardous voltage wiring is performed only by qualified personnel
adhering to local electrical standards.
Caution Do not mix hazardous voltage circuits and human-accessible circuits on the same
module.
Caution Make sure that devices and circuits connected to the module are properly
insulated from human contact.
Caution 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 Assembling the High Voltage Screw Terminal Backshell section for more information.