National Instruments cFP-RTD-122 用户手册
© National Instruments Corp.
5
FP-RTD-122 and cFP-RTD-122
Figure 3. [c]FP-RTD-122 Input Circuitry
Taking Measurements from Three-Wire RTDs
Three-wire RTDs often have a wire of one color (usually white,
sometimes red) for positive excitation, and two wires of another
color (usually red, sometimes black). Connect the positive
excitation wire to the EX+ terminal of the module, and connect the
other two wires to the SENSE and COM terminals.
sometimes red) for positive excitation, and two wires of another
color (usually red, sometimes black). Connect the positive
excitation wire to the EX+ terminal of the module, and connect the
other two wires to the SENSE and COM terminals.
Figure 4. Three-Wire RTD Connections on One Channel
Taking Measurements from Four-Wire RTDs
For the best accuracy, use the NI [c]FP-RTD-124 for input from
four-wire RTDs. Otherwise, leave any one of the RTD wires
unconnected and connect the remaining three as you would for a
three-wire RTD. Refer to Figure 5.
four-wire RTDs. Otherwise, leave any one of the RTD wires
unconnected and connect the remaining three as you would for a
three-wire RTD. Refer to Figure 5.
RTD
[c]FP-RTD-122
Pulsed
16-bit
ADC
Input
Circuitry
EX+
SENSE
COM
3-wire RTD
[c]FP-RTD-122
EX+
SENSE
COM