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Spectrum Controls 1746sc-NI8u User Manual

Page 30

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18

SLC 500

Universal Analog Input Module

RTD Type

V/

°

C

100

Pt 385

58µV/

°

C

200

Pt 385

116µV/

°

C

500

Pt 385

290µV/

°

C

1000

Pt 385

580µV/

°

C

100

Pt 3916

68µV/

°

C

200

Pt 3916

136µV/

°

C

500

Pt 3916

340µV/

°

C

1000

Pt 3916

680µV/

°

C

10

Cu 426

4.3µV/

°

C

120

Ni 618

110µV/

°

C

120

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):