Wiring the [c]fp-rtd-124, Table 1. terminal assignments, Taking rtd measurements withthe[c]fp-rtd-124 – National Instruments cFP-RTD-124 User Manual
Page 4: Taking rtd measurements with the [c]fp-rtd-124
FP-RTD-124 and cFP-RTD-124
4
ni.com
Wiring the [c]FP-RTD-124
The FP-TB-x terminal bases have connections for each of the eight
input channels on the FP-RTD-124. The cFP-CB-x connector
blocks provide the same connections for the cFP-RTD-124.
Table 1 lists the terminal assignments for the signals associated
with each channel.
If you are using shielded wiring, you can reduce input signal noise
by connecting one end of the shield to the COM terminal. Do not
connect the shield to any of the wires at the signal end.
Taking RTD Measurements
with the [c]FP-RTD-124
The [c]FP-RTD-124 has eight input channels. All eight channels
share a common ground that is isolated from other modules in the
FieldPoint system. Each channel pulses a 2 mA excitation current
out of the EXCITE
+ terminal. The excitation current returns
through the COM terminal. The SENSE+ and SENSE– terminals
measure resistance and compensate for lead resistance errors. Each
channel is filtered, then sampled by a 16-bit analog-to-digital
converter.
Table 1. Terminal Assignments
Channel
Terminal Numbers
SENSE+
SENSE–
EXCITE+
COM
0
1
2
17
18
1
3
4
19
20
2
5
6
21
22
3
7
8
23
24
4
9
10
25
26
5
11
12
27
28
6
13
14
29
30
7
15
16
31
32