NI 9421/9423
20
ni.com
meas
u
rements of voltages from specially protected secondary
circ
u
its. S
u
ch voltage meas
u
rements incl
u
de signal levels, special
eq
u
ipment, limited-energy parts of eq
u
ipment, circ
u
its powered by
reg
u
lated low-voltage so
u
rces, and electronics.
Note
Do
not
connect the NI 9421 with DSUB
to
signals or
u
se for meas
u
rements within Meas
u
rement
Categories II, III, or IV.
Hazardous Locations
U.S. (UL) .......................................... Class I, Division 2,
Gro
u
ps A, B, C, D, T4;
Class I, Zone 2,
AEx nC IIC T4
Canada (C-UL) ................................. Class I, Division 2,
Gro
u
ps A, B, C, D, T4;
Class I, Zone 2,
Ex nC IIC T4
E
u
rope (DEMKO)............................. Ex nC
IIC T4
