National Instruments SCXI Series - Current Excitation

Chapter 4 Connecting and Using Accessories and Transducers
© National Instruments Corporation 4-21 Getting Started with SCXI
Figure 4-12 shows how to connect commonly configured RTDs to the
SCXI-1121 module.
Figure 4-12. SCXI-1121 RTD Configurations
Note: Four-wire RTDs produce more accurate temperature measurements than either
two-wire or three-wire RTDs, which introduce lead resistance errors.
b. Three-Wire RTD Configurationa. Four-Wire RTD Configuration
SCXI-1121 Module with
Current Excitation Enabled
EX+
CH+
EX
–
I
EX
+
CH –
RTD
Red
Black
Red
Black
c. Two-Wire RTD Configuration
EX+
CH+
EX
–
I
EX
+
CH
–
RTD
Red
Black
You must make
these connections
SCXI-1121 Module with
Current Excitation Enabled
EX+
CH+
EX
–
I
EX
+
CH
–
RTD
Red
Black
Black
You must make
this connection
SCXI-1121 Module with
Current Excitation Enabled
•
= Connection to Terminal Block
–
–
–