©
National Instruments Corp.
17
NI 9219 Operating Instructions
Figure 10.
Connections in Half-Bridge and Full-Bridge Modes
Thermocouple Mode
In Thermocouple mode, connect the positive end of the
thermocouple to HI and the negative end of the thermocouple to
LO. This mode uses the ±125 mV range of the ADC to return a
voltage reading. Use shielded cables and twisted pair wiring and
ground the shielded cables. Each channel has a built-in thermistor
for cold-junction compensation (CJC) calculations. For improved
CJC sensor accuracy, operate the NI 9219 in a stable temperature
1
The dotted line repre
s
ent
s
the portion of the circ
u
it th
a
t i
s
connected
only in F
u
ll-Bridge mode.
HI
LO
EX+
EX–
NI 9219
R
1
R
2
R
3
R
4
ADC
Wire
Wire
1