©
National Instruments Corporation
15
NI USB-9421 User Guide and Specifications
Bus Interface
USB specification .................................. USB 2.0 Hi-Speed
Physical Characteristics
Dimensions
With screw terminal........................ 14.0 cm
×
8.8 cm
×
2.5 cm
(5.52 in.
×
3.47 in.
×
1.00 in.)
With 25-pin D-SUB ........................ 12.6 cm
×
8.8 cm
×
2.5 cm
(4.95 in.
×
3.47 in.
×
1.00 in.)
Screw-terminal wiring............................ 12 to 24 AWG copper conductor
wire with 10 mm (0.39 in.) of
insulation stripped from the end
Torque for screw terminals .................... 0.5 – 0.6 N · m (4.4 – 5.3 lb · in.)
Weight
With screw terminal........................ Approx. 250 g (8.8 oz)
With D-SUB ................................... Approx. 245 g (8.6 oz)
Safety
If you need to clean the module, wipe it with a dry towel.
Safety Voltages
NI USB-9421 with Screw Terminal Safety Voltages
Connect only voltages that are within these limits.
Channel-to-COM ................................... 30 V max
Isolation
Channel-to-channel ......................... No isolation between channels
Channel-to-earth ground
Withstand................................. 2,300 V
rms
, verified by a 5 second
dielectric withstand test
Continuous............................... 250 V
rms
,
Measurement Category II
Measurement Category II is for measurements performed on circuits
directly connected to the electrical distribution system. This category refers
to local-level electrical distribution, such as that provided by a standard
wall outlet (for example, 115 V for U.S. or 230 V for Europe).
