V+
V+
Equal line resistance here creates
a small common-mode voltage
which is rejected by INA114.
1
RTD
2
REF200
100µA
R
G
INA114
Ref
V
O
R
Z
3
Resistance in this line causes
a small common-mode voltage
which is rejected by INA114.
V
O
= 0V at R
RTD
= R
Z
FIGURE 8. RTD Temperature Measurement Circuit.
V+
2
10.0V
6
REF102
R
1
27k
Ω
R
4
80.6k
Ω
(2)
4
1N4148
(1)
Cu
K
Cu
R
2
5.23k
Ω
R
7
1M
Ω
INA114
Ref
V
O
R
3
100
Ω
R
5
50
Ω
R
6
100
Ω
Zero Adj
ISA
TYPE
E
J
K
T
MATERIAL
Chromel
Constantan
Iron
Constantan
Chromel
Alumel
Copper
Constantan
SEEBECK
COEFFICIENT
(
µ
V/
°
C)
58.5
50.2
39.4
38.0
R
2
(R
3
= 100Ω)
3.48kΩ
4.12kΩ
5.23kΩ
5.49kΩ
R
4
(R
5
+ R
6
= 100Ω)
56.2kΩ
64.9kΩ
80.6kΩ
84.5kΩ
NOTES: (1) –2.1mV/°C at 200µA. (2) R
7
provides down-scale burn-out indication.
FIGURE 9. Thermocouple Amplifier With Cold Junction Compensation.
®
11
INA114
BURR-BROWN [ BURR-BROWN CORPORATION ]
