©
National Instruments Corp.
19
NI 9421/9423
that provided by a standard wall o
u
tlet, for example, 115 V for U.S.
or 230 V for E
u
rope.
Caution
Do
not
connect the NI 9421/9423 with screw
terminal to signals or
u
se for meas
u
rements within
Meas
u
rement Categories III or IV.
NI 9421 with DSUB Safety Voltages
Connect only voltages that are within the following limits.
Channel-to-COM .............................. 30 V max
Isolation
Channel-to-channel .................... None
Channel-to-earth gro
u
nd
Contin
u
o
u
s ........................... 60 VDC,
Meas
u
rement Category I
Withstand ............................. 1,000 V
rms
, verified by a 5 s
dielectric withstand test
Meas
u
rement Category I is for meas
u
rements performed on
circ
u
its not directly connected to the electrical distrib
u
tion system
referred to as
MAINS
voltage. MAINS is a hazardo
u
s live electrical
s
u
pply system that powers eq
u
ipment. This category is for