Spectrum Controls 1746sc-NI8u User Manual
Page 30
18
SLC 500
™
Universal Analog Input Module
RTD Type
V/
°
C
100
Ω
Pt 385
58µV/
°
C
200
Ω
Pt 385
116µV/
°
C
500
Ω
Pt 385
290µV/
°
C
1000
Ω
Pt 385
580µV/
°
C
100
Ω
Pt 3916
68µV/
°
C
200
Ω
Pt 3916
136µV/
°
C
500
Ω
Pt 3916
340µV/
°
C
1000
Ω
Pt 3916
680µV/
°
C
10
Ω
Cu 426
4.3µV/
°
C
120
Ω
Ni 618
110µV/
°
C
120
Ω
Ni 672
130µV/
°
C
The accuracies specified for the NI8u RTDs do not include errors due to
lead resistance imbalances.
Important: To ensure temperature or resistance value accuracy, the
resistance difference of the cable lead wires must be equal to or less
than 0.01 ohms.
There are several ways to insure that the lead values match as closely as
possible. They are as follows:
* Keep total lead resistance as small as possible, and less than 25 ohms.
* Use quality cable that has a small tolerance impedance rating.
* Use a heavy gauge lead wire which has less resistance per foot.
Preparing and
Wiring the Cables
To prepare and connect cable leads and drain wires, follow these
steps:
Signal Wires
(Remove foil shield and drain wire
from sensor-end of cable.)
Cable
Signal Wires
(At the module-end of the cable, extract
the drain wire but remove the foil shield.)
Drain Wire
1. At each end of the cable, strip some casing to expose individual
wires.
2. Trim signal wires to 5-inch lengths beyond the cable casing. Strip
about 3/16 inch (4.76 mm) of insulation to expose the ends of the
wires.
3. At the module-end of the cables (see figure above):