National Instruments NI USB-9421 用户手册

A high voltage screw terminal backshell must be installed when using hazardous 

voltages (>42.4 V

pk

, 60 VDC). 

Table 2 illustrates the accessories available from 

ni.com

 for use with the 

NI USB-9421. 

Table 1.  LED State/Device Status

Not lit

Device not connected or in suspend.

On, not blinking

Device connected, but no module installed.

Single-blink

Operating normally.

Double-blink

Operating normally.

Quadruple-blink

Device error. Refer to 

ni.com/support

.

Table 2.  Accessories

USB-9421 with Screw Terminal

NI 9932

10-terminal, detachable, high 
voltage, screw terminal backshell

1

USB-9421 with 25-pin D-SUB

NI 9934

25-pin D-SUB connector

1 

For more information about installing the backshell, refer to the 

 

section.